Effective dynamics for a spin-1/2 particle constrained to a curved layer with inhomogeneous thickness

We derive an effective Hamiltonian for a spin-1/2 particle confined within a curved thin layer with non-uniform thickness using the confining potential approach.Our analysis reveals the presence of a pseudo-magnetic field and effective spin–orbit interaction(SOI)arising from the curvature,as well as an effective scalar potential resulting from variations in thickness.Importantly,we demonstrate that the physical effect of additional SOI from thickness fluctuations vanishes in low-dimensional systems,thus guaranteeing the robustness of spin interference measurements to thickness imperfection.Furthermore,we establish the applicability of the effective Hamiltonian in both symmetric and asymmetric confinement scenarios,which is crucial for its utilization in one-side etching systems.

Nonlinear modes coupling of trapped spin-orbit coupled spin-1 Bose-Einstein condensates

We study analytically and numerically the nonlinear collective dynamics of quasi-one-dimensional spin-orbit coupled spin-1 Bose-Einstein condensates trapped in harmonic potential.The ground state of the system is determined by minimizing the Lagrange density,and the coupled equations of motions for the center-of-mass coordinate of the condensate and its width are derived.Then,two low energy excitation modes in breathing dynamics and dipole dynamics are obtained analytically,and the mechanism of exciting the anharmonic collective dynamics is revealed explicitly.The coupling among spin-orbit coupling,Raman coupling and spin-dependent interaction results in multiple external collective modes,which leads to the anharmonic collective dynamics.The cooperative effect of spin momentum locking and spin-dependent interaction results in coupling of dipolar and breathing dynamics,which strongly depends on spin-dependent interaction and behaves distinct characters in different phases.Interestingly,in the absence of spin-dependent interaction,the breathing dynamics is decoupled from spin dynamics and the breathing dynamics is harmonic.Our results provide theoretical evidence for deep understanding of the ground sate phase transition and the nonlinear collective dynamics of the system.

猪伪狂犬病毒EP0蛋白拮抗宿主蛋白Spindlin1抗病毒作用的研究

为了分析Spindlin1 (Spin1)蛋白对猪伪狂犬病毒(PRV)复制的影响,本研究利用GE Dharmacon siRNA网站设计3条Spin1 si RNA (siSpin1-376、siSpin1-537与si Spin1-654),将其以1∶1∶1的比例混合,以30 pmol的剂量转染PK-15细胞,转染后48 h感染PRV He N1株,并分别于感染后6 h、12 h、18 h和24 h收集细胞及上清样品,进行病毒的TCID50测定,结果显示,与对照组相比,感染后12 h,干扰Spin1的表达能够显著促进PRV在PK-15细胞中的增殖(P<0.05)。将PRV以MOI 0.1感染PK-15细胞后不同时间,利用western blot检测PRV感染对Spin1蛋白表达水平的影响,结果显示,与转染siRNA-NO的对照组相比,PRV感染后12 h细胞中的Spin1蛋白表达水平显著下降(P<0.05),其余时间段与对照组均无显著差异。为了阐明PRV拮抗Spin1抗病毒作用的分子机制,本研究分别构建PRV早期蛋白EP0与Spin1的真核表达质粒并分别经PCR及测序鉴定正确后共转染人胚胎肾细胞(HEK293FT),western blot结果显示,与单独转染Spin1表达质粒的细胞相比,共转染Spin1与EP0表达质粒细胞中Spin1的表达水平明显下调。进一步利用免疫共沉淀试验(Co-IP)分析二者的相互作用情况,结果显示,EP0与Spin1在共转染的细胞中存在相互作用。上述结果表明,PRV EP0蛋白能够通过与Spin1蛋白的相互作用下调其的表达。本研究发现了一个新的能够抑制PRV复制的宿主蛋白,并阐明了PRV拮抗宿主抗病毒因子的一种新机制,为揭示PRV的致病机理以及新型药物的研发提供参考。

SPIN1与恶性肿瘤

SPIN1(spindlin 1)是一种组蛋白修饰阅读器蛋白,通过识别组蛋白H3第4位赖氨酸三甲基化(trimethylation of lysine 4 on histone H3 protein subunit,H3K4me3)促进核糖体RNA的表达,从而影响表观遗传的调控,以此发挥其生物学作用。SPIN1在多种恶性肿瘤中过表达,可受多种长链非编码RNA(long non-coding RNA,lncRNA)、微RNA(microRNA,miRNA)及环状RNA(circularRNA,circRNA)的负向调控,并可由转录因子腺病毒E2因子1(adenovirus E2 factor 1,E2F1)转录激活,通过Wnt、磷脂酰肌醇3激酶/蛋白激酶B(phosphatidylinositol 3-kinase/protein kinase B,PI3K/Akt)、转染过程重排(rearrangement during transfection,RET)因子、鼠双微体基因-p53(murine double minute 2-p53,MDM2-p53)等与肿瘤发生相关的信号通路,促进肿瘤的发生、发展,并与不良预后密切相关。随着对SPIN1的研究越来越深入,发现SPIN1可作为多种恶性肿瘤治疗的潜在靶点。目前已开发出针对SPIN1和H3K4me3间相互作用的抑制剂,以此阻断SPIN1的致癌能力。

考虑源荷不确定性和N-1安全约束的电力系统优化调度

大规模风电并网增加了系统运行的不确定因素,文章利用快速可调资源平抑风电和负荷波动引发的功率不平衡,并考虑备用调用过程减少对系统潮流的影响。首先分析了风电和负荷预测误差的概率分布模型;然后,建立含N-1网络安全机会约束和旋转备用机会约束的电力系统优化调度模型,以系统调度总成本最小为目标优化机组出力;最后,基于起作用整数变量的识别方法的Benders分解法处理N-1网络安全约束,提高求解效率。利用修正的IEEE30节点系统,验证了所提模型能够保障系统备用可用性、经济性和安全性,充分挖掘抽水蓄能的快速可调能力。

Spin-1 Blume-Capel model with longitudinal random crystal and transverse magnetic fields:A mean-field approach

The spin-1 Blume–Capel model with transverse and longitudinal external magnetic fields h, in addition to a longitudinal random crystal field D, is studied in the mean-field approximation. It is assumed that the crystal field is either turned on with probability p or turned off with probability 1 p on the sites of a square lattice. Phase diagrams are then calculated on the reduced temperature crystal field planes for given values of γ=Ω/J and p at zero h. Thus, the effect of changing γ and p are illustrated on the phase diagrams in great detail and interesting results are observed.

Gapped Spin-1/2 Spinon Excitations in a New Kagome Quantum Spin Liquid Compound Cu_3Zn(OH)_6FBr

We report a new kagome quantum spin liquid candidate CuaZn（OH）6FBr, which does not experience any phase transition down to 50inK, more than three orders lower than the antiferromagnetic Curie-Weiss temperature （-200 K）. A clear gap opening at low temperature is observed in the uniform spin susceptibility obtained from 19F nuclear magnetic resonance measurements. We observe the characteristic magnetic field dependence of the gap as expected for fractionalized spin-1/2 spinon excitations. Our experimental results provide firm evidence for spin fractionalization in a topologically ordered spin system, resembling charge fraetionalization in the fractional quantum Hall state.

Discovery of Fractionalized Neutral Spin-1/2 Excitation of Topological Order

After the discovery of fraction quantum Hall states in the 1980s, it became more and more clear that Landau symmetry breaking theory does not describe all possible quantum phases of matter. The new quan- tum phases of matter were called topologically ordered phases（for gapped cases） or quantum ordered phases （for gapless cases）, which correspond to pat- terns of many-body entanglement. One may won- der： besides quantum Hall systems, are there other systems that realize the new topological/quantum order？

Thermal entanglement in two-qutrit spin-1 anisotropic Heisenberg model with inhomogeneous magnetic field

The thermal entanglement of a two-qutrit spin-1 anisotropic Heisenberg XXZ chain in an inhomogeneous magnetic field is studied in detail. The effects of the external magnetic field （B）, a parameter b which controls the inhomogeneity of B, and the bilinear interaction parameters Jx = Jy ≠ Jz on the thermal variation of the negativity are studied in detail. It is found that negativity N decreases when the values of magnetic field, inhomogeneity b and temperature are increasing. In addition, N remains at higher temperatures for higher values of Jz and lower values of B and b.

Soliton breathers in spin-1 Bose–Einstein condensates

We consider a spin-1 Bose-Einstein condensate trapped in a harmonic potential with different nonlinearity coeffi- cients. We illustrate the dynamics of soliton breathers in two-component and three-component states by numerically solv- ing the one-dimensional time-dependent coupled Gross-Pitaecskii equations （GPEs）. We present that two condensates with repulsive interspecies interactions make elastic collision and novel soliton breathers are created in two-component state. We also demonstrate novel soliton breathers in three-component state with attractive coupling constants. Furthermore, possible reasons for creating soliton breathers are discussed.

LnCu_(3)(OH)_(6)Cl_(3) (Ln=Gd, Tb, Dy): Heavy lanthanides on spin-1/2 kagome magnets

The spin-1/2 kagome antiferromagnets are key prototype materials for studying frustrated magnetism.Three isostructural kagome antiferromagnets LnCu_(3)(OH)_(6)Cl_(3)(Ln=Gd,Tb,Dy)have been successfully synthesized by the hydrothermal method.LnCu_(3)(OH)_(6)Cl_(3) adopts space group P3m1 and features the layered Cu-kagome lattice with lanthanide Ln3+cations sitting at the center of the hexagons.Although heavy lanthanides(Ln=Gd,Tb,Dy)in LnCu_(3)(OH)_(6)Cl_(3) provide a large effective magnetic moment and ferromagnetic-like spin correlations compared to light-lanthanides(Nd,Sm,Eu)analogues,Cu-kagome holds an antiferromagnetically ordered state at around 17 K like YCu_(3)(OH)_(6)Cl_(3).

The Mixed Spin-1/2 and Spin-1 Ising–Heisenberg Model in the Mean-Field Approximation: a New Approach

Thermodynamic properties of the mixed spin-1 and spin-1/2 Ising-Heisenberg model are studied on a honeycomb lattice using a new approach in the mean-field approximation to analyze the effects of longitudinal Dz and transverse Dx crystal fields. The phase diagrams are calculated in detail by studying the thermal variations of the order parameters, i.e., magnetizations and quadrupole moments, and compared with the literature to assess the reliability of the new approach. It is found that the model yields both second- and first-order phase transitions, and tricritical points. The compensation behavior of the model is also investigated for the sublattice magnetizations, and longitudinal and transverse quadrupolar moments. The latter type of compensation is observed in the literature but its possible importance is overlooked.

Energy Levels of Spin-1/2 Particles with Yukawa Interaction

In this article, Yukawa interaction is used to study the relativistic spin-1/2 particles and obtain their energy levels. The role of Yukawa potential on the spin and pseudospin symmetry solution is investigated systematically by solving the Dirac equation with attractive scalar S(r) and repulsive vector V(r) potentials. Bound state spectrum and wave functions of Yukawa potential are obtained. It is found that the energy eigenvalues strongly depend on the potential parameters.

Weak Nonlinear Matter Waves in a Trapped Spin-1 Condensates

The dynamics of the weak non//near matter sofitary waves in a spin-1 condensates with harmonic external potential are investigated analytically by a perturbation method. It is shown that, in the small amplitude limit, the dynamics of the solitary waves are governed by a variable-coetficient Korteweg-de Vries （KdV） equation. The reduction to the （KdV） equation may be useful to understand the dynamics of nonlinear matter waves in spinor BECs. The analytical expressions for the evolution of soliton show that the small-amplitude vector solitons of the mixed types perform harmonic oscillations in the presence of the trap. Furthermore, the emitted radiation profiles and the soliton oscillation frequency are also obtained.

Assessment the Optimal Effect of Time of Repetition: Extrinsic Pulse Parameter on Gd-DTPA Enhanced, Spin-Echo T1-Weighted MR Images under Low Magnetic Field Strength

The contrast agent concentration, the time of repetition (TR) and magnetic field strength are significant parameters that influence for the accurate signal intensity (SI) in quantitative Magnetic Resonance Imaging (MRI). Therefore, this study was conducted to investigate and refine the dependence and the optimal effect of Time of Repetition (TR) on the relationship between signal intensity and Gd-DTPA (Gadolinium-diethylene-triaminepenta-acetic acid) concentration, after applying two-dimensional (2D) Spin Echo (SE) pulse sequence under low-field MRI. In addition to that, the optimal concentration of Gd-DTPA at given sequence parameters at low-field MRI was also evaluated. A water-filled phantom was constructed for a range of Gd-DTPA concentrations (0 - 6 mmol/L) and the mean signal intensities (SIs) were assessed in the defined region of interest on T1-weighted images with different TR values (40 - 2000 ms). The generated signal-concentration curves for Gd-DTPA revealed that increasing TR was associated with the increase of the overall SIs and the maximum relationship between SI to concentration. Moreover, the required Gd-DTPA concentration to produce the maximum SI was associated to decrease with the increase of TR. In addition to this, the application of beyond 100 ms TR values in this study with relatively higher concentrations (beyond 1 - 2 mmol/L) has resulted predominantly non-linear patterns in the signal-concentration curves and it appears the saturation or decay of the SIs due to T2 effect. From these results, it can be suggested that the selection of relatively lower Gd-DTPA concentration ( mmol/L) with less than 800 ms (<800 ms) TR values can produce a better linear relationship between the concertation and SIs in T1-weighted SE low field contrast-enhanced MRI. Furthermore, this study also outlined the significance and necessity of the optimization of TR in SE sequence in low field MRI prior to a particular examination.

Monitoring the autoproteolysis of hiv-1 protease by site-directed spin-labeling and electron paramagnetic resonance spectroscopy

Site-directed spin-labeling with continuous wave electron paramagnetic resonance spectroscopy was used to monitor autoproteolysis of HIV-1 protease, an enzyme essential for viral maturation. Two protein constructs were examined, namely subtype F and the circulating recombinant form CRF01_A/E. As the protease undergoes self-cleavage, protein unfolds and small peptide fragments containing the spin label are generated, which collectively give rise to a sharp spectral component that is easily discernable in the high-field resonance line in the EPR spectrum. By monitoring the intensity of this spectral component over time, the autoproteolytic stability of each construct was characterized under various conditions. Data were collected for samples stored at 4 °C, 25 °C, and 37 °C, and on a subtype F HIV-1 protease sample stored at 25 °C and containing the FDA-approved protease inhibitor Tipranavir. As expected, the rate of autoproteolysis decreased as the storage temperature was lowered. Minimal autoproteolysis was seen for the sample that contained Tipranavir, providing direction for future spectroscopic studies of active protease samples. When compared to standard methods of monitoring protein degradation such as gel electrophoresis or chromatographic analyses, spin-labeling with CW EPR offers a facile, real-time, non-consuming way to monitor autoproteolysis or protein degradation. Additionally, mass spectrometry studies revealed that the N-termini of both constructs are sensitive to degradation and that the sites of specific autoproteolysis vary.

MDM2、p53、SPIN1mRNA在口腔癌组织中的表达及其相关性研究

目的:研究口腔癌组织中MDM2、p53、SPIN1mRNA的表达,探讨其相关性及在肿瘤发生发展中的作用。方法:应用实时定量PCR(RT-PCR)对28例口腔癌及癌旁组织标本的MDM2、p53、SPIN1mRNA水平进行检测。结果:28例口腔癌及癌旁正常组织的MDM2、p53mRNA的表达水平差异显著,前者在口腔癌组织中表达较高(P<0.01),后者在口腔癌中的表达较低(P<0.05)。SPIN1mRNA在两种组织中的表达无明显差异。MDM2mRNA在口腔癌中的表达,随病理分化的提高的而增高(P<0.01,P<0.05)。p53、SPIN1mRNA的表达和肿瘤分化无关(P>0.05)。口腔癌组织中MDM2、p53、SPIN1mRNA表达无显著相关性(P>0.05)。结论:MDM2、p53基因在口腔癌发生发展中可能发挥重要作用。SPIN1基因在口腔癌的发生发展过程中可能不发挥主要作用。

The Antioxidization Effects of TP-5, Thy(1[Lys23] and Their Spin Labeled Derivatives

TP-5 and Thy(1, synthesized by solid phase synthesis, have the effect to restrain the formation of superoxide anion in xanthine oxidase system in vitro. The formations of lipid peroxide in several organs (such as liver, brain and thymus) of the mice treated with TP-5, TP-5(R, active fragment of Thy(1 and active fragment of Thy(1(R of 10 (g(kg(d-1 for 10 d were decreased. That means these peptides possess the capability of antioxidezation.

MDM2、SPIN1 mRNA在喉癌组织中的表达及其相关性研究

目的研究MDM2、SPIN1 mRNA在喉癌组织中的表达,并探讨其相关性。方法收集37例喉癌患者手术切除的喉癌组织标本进行相关指标检测,另取癌旁正常组织作为对照。采用RT-PCR法分别检测标本中MDM2、SPIN1 mRNA的表达水平,并进行对比分析。结果喉癌组织MDM2 mRNA表达高于正常组织(P<0.01),且病理分化程度越高,其表达越高;SPIN1 mRNA表达与病理分化程度无显著相关性(P>0.05)。结论 MDM2 mRNA可能与喉癌进程有直接关系,而SPIN1 mRNA与喉癌无显著相关性。

动脉自旋标记和扩散张量成像评估脑胶质瘤IDH1基因表型的价值研究

目的 探讨常规MRI联合动脉自旋标记(arterial spin labeling,ASL)成像、扩散张量成像(diffusion tensor imaging,DTI)在评估胶质瘤异柠檬酸脱氢酶1(isocitrate dehydrogenase 1,IDH1)表型中的价值。材料与方法 回顾性分析2019年9月至2021年12月经病理证实为胶质瘤患者病例61例,根据基因或免疫组化检测IDH1表型,分为IDH1突变型(IDH1_(mutant),IDH1_(mut))组和IDH1野生型(IDH1 wild,IDH1_(wt))组,术前行颅脑MRI常规检查及ASL、DTI检查。评估IDH1_(mut)、IDH1_(wt)胶质瘤常规MRI特征(大小、位置、边缘、坏死囊变、出血、水肿和强化),测量肿瘤实性区、瘤周区的各向异性分数(anisotropy fraction,FA)、表观扩散系数(apparent diffusion coefficient,ADC)、脑血流量最大值(_(max)imum cerebral blood flow,CBF_(max))、平均值(_(mean) cerebral blood flow,CBF_(mean)),计算相对脑血流量最大值(relativer CBF_(max),r CBF_(max))、相对脑血流量平均值(relativer CBF_(mean),r CBF_(mean))。采用SPSS 25.0进行统计学分析。所有样本组间分析采用独立样本t检验或非参数检验进行分析,建立多因素logistic回归模型并绘制受试者工作特征(receiver operating characteristic,ROC)曲线预测其诊断效能。结果 本研究共纳入胶质瘤患者病例61例:IDH_(mut)19例、IDH1_(wt)42例。IDH1_(mut)与IDHwt胶质瘤的位置、强化、水肿、肿瘤实性区CBF、瘤周区ADC具有显著性差异(P<0.05);IDH1_(wt)肿瘤实性区CBF_(max)、CBF_(mean)、r CBF_(max)、r CBF_(mean)高于IDH1_(mut)型(P<0.05),曲线下面积(area under the curve,AUC)分别为0.879、0.832、0.806、0.875;IDH1_(wt)瘤周ADC值高于IDH1_(mut)(P<0.05)。肿瘤实质区CBF_(mean)联合瘤周ADC诊断IDH1表型的效能最高(AUC=0.892)。多因素logistic回归显示肿瘤实体区CBF是胶质瘤IDH1表型预测的独立风险因素。结论 常规MRI特征、ASL及DTI对胶质瘤IDH1表型评估具有重要临床价值,联合肿瘤实质区CBF、瘤周ADC值可进一步提高胶质瘤IDH1表型的诊断效能。