A contradictory phenomenon of thicken pericardium and cardiac compression without inferior vena cava dilation:sign of IVC escape

A 77-year-old female presented with shortness of breath and tightness of chest was admitted.Her past medical history included hypertension and she has been taking nifedipine regularly.Two years before,she was diagnosed with pericardial effusion(Figure 1)and had pericardiocentesis drainage.On physical examination,her blood pressure was 151/100 mm-Hg and her pulse rate was 91 beats/min.

Strain drived band aligment transition of the ferromagnetic VS_(2)/C_(3)N van der Waals heterostructure

Exploring two-dimensional(2D)magnetic heterostructures is essential for future spintronic and optoelectronic devices.Herein,using first-principle calculations,stable ferromagnetic ordering and colorful electronic properties are established by constructing the VS_(2)/C_(3)N van der Waals(vdW)heterostructure.Unlike the semiconductive properties with indirect band gaps in both the VS2 and C3N monolayers,our results indicate that a direct band gap with type-Ⅱband alignment and p-doping characters are realized in the spin-up channel of the VS_(2)/C_(3)N heterostructure,and a typical type-Ⅲband alignment with a broken-gap in the spin-down channel.Furthermore,the band alignments in the two spin channels can be effectively tuned by applying tensile strain.An interchangement between the type-Ⅱand type-Ⅲband alignments occurs in the two spin channels,as the tensile strain increases to 4%.The attractive magnetic properties and the unique band alignments could be useful for prospective applications in the next-generation tunneling devices and spintronic devices.

Structures and ion transport mechanisms of plant high-affinity potassium transporters

Plant high-affinity K^(+) transporters(HKTs)mediate Na^(+) and K^(+) uptake,maintain Na^(+)/K^(+) homeostasis,and therefore play crucial roles in plant salt tolerance.In this study,we present cryoelectron microscopy structures of HKTs from two classes,classI HKT1;1 from Arabidopsis thaliana(AtHKT1;1)and class II HKT2;1 from Triticum aestivum(TaHKT2;1),in both Na^(+) -and K^(+) -bound states at 2.6-to 3.0-A resolutions.BothAtHKT1;1and TaHKT2;1function ashomodimers.Each HKT subunit consists of four tan-dem domain units(D1-D4)with a repeated K^(+) -channel-like M-P-M topology.In each subunit,D1-D4 assemble into an ion conduction pore with a pseudo-four-fold symmetry.Although both TaHKT2;1and AtHKT1;1 have only one putative Na^(+) ion bound in the selectivity filter with a similar coordination pattern,the two HKTs display different K^(+) binding modes in the filter.TaHKT2;1 has three K^(+) ions bound in the selec-tivity filter,but AtHKT1;1 has only two K^(+) ions bound in the filter,which has a narrowed external entrance due to the presence of a Ser residue in the first filter motif.These structures,along with compu-tational,mutational,and electrophysiological analyses,enable us to pinpoint key residues that are critical for the ion selectivity of HKTs.The findings provide new insights into the ion selectivity and ion transport mechanisms of plant HKTs and improve our understanding about how HKTs mediate plant salt tolerance and enhance crop growth.

一类Filippov型HR神经元模型的全局动力学分析

基于电磁辐射下的HR神经元模型,引入一种以膜电位为阈值的非光滑控制策略,即确定与电磁感应强度和外部刺激电流相对应的切换函数,从而建立一类四维Filippov型HR神经元模型。利用稳定性理论和数值模拟方法讨论2个子系统平衡点的存在性、稳定性和全局分岔行为。另外,基于双参数分岔分析,研究子系统的双稳态行为和演化模式。进一步,利用Filippov凸组合方法和Utkin等度控制方法分析系统的各类平衡点和滑膜动力学的存在性。最后,采用快-慢动力学的方法揭示阈值控制策略下的滑动放电模式和多稳态特征。