基于符号数值计算的代数曲线区间插值

本文研究的代数曲线区间插值问题,是针对预先给定平面上的若干矩形小邻域,构造经过它们的次数最低的代数曲线、项数最少的代数曲线以及系数是整数的代数曲线.本文将上述问题转化为优化问题,给出基于符号数值计算和Lagrange乘子法的求解方法,应用这一方法解决了几个具体的有趣问题,包括基于太阳系行星、小行星和矮行星的轨道数据重新发现Kepler第三定律.

HIF-1αpromotes virus replication and cytokine storm in H1N1 virus-induced severe pneumonia through cellular metabolic reprogramming

The mortality of patients with severe pneumonia caused by H1N1 infection is closely related to viral replication and cytokine storm.However,the specific mechanisms triggering virus replication and cytokine storm are still not fully elucidated.Here,we identified hypoxia inducible factor-1α(HIF-1α)as one of the major host molecules that facilitates H1N1 virus replication followed by cytokine storm in alveolar epithelial cells.Specifically,HIF-1αprotein expression is upregulated after H1N1 infection.Deficiency of HIF-1αattenuates pulmonary injury,viral replication and cytokine storm in vivo.In addition,viral replication and cytokine storm were inhibited after HIF-1αknockdown in vitro.Mechanistically,the invasion of H1N1 virus into alveolar epithelial cells leads to a shift in glucose metabolism to glycolysis,with rapid production of ATP and lactate.Inhibition of glycolysis significantly suppresses viral replication and inflammatory responses.Further analysis revealed that H1N1-induced HIF-1αcan promote the expression of hexokinase 2(HK2),the key enzyme of glycolysis,and then not only provide energy for the rapid replication of H1N1 virus but also produce lactate,which reduces the accumulation of the MAVS/RIG-I complex and inhibits IFN-α/βproduction.In conclusion,this study demonstrated that the upregulation of HIF-1αby H1N1 infection augments viral replication and cytokine storm by cellular metabolic reprogramming toward glycolysis mainly through upregulation of HK2,providing a theoretical basis for finding potential targets for the treatment of severe pneumonia caused by H1N1 infection.

Dynamic immune recovery process after liver transplantation revealed by single-cell multi-omics analysis

Elucidating the temporal process of immune remodeling under immunosuppressive treatment after liver transplantation(LT)is critical for precise clinical management strategies.Here,we performed a single-cell multi-omics analysis of peripheral blood mononuclear cells(PBMCs)collected from LT patients(with and without acute cellular rejection[ACR])at 13 time points.Validation was performed in two independent cohorts with additional LT patients and healthy controls.Our study revealed a four-phase recovery process after LT and delineated changes in immune cell composition,expression programs,and interactions along this process.The intensity of the immune response differs between the ACR and non-ACR patients.Notably,the newly identified inflamed NK cells,CD14+RNASE2+monocytes,and FOS-expressing monocytes emerged as predictive indicators of ACR.This study illuminates the longitudinal evolution of the immune cell landscape under tacrolimus-based immunosuppressive treatment during LT recovery,providing a four-phase framework that aids the clinical management of LT patients.

点集拓扑学之杨忠道定理的一个机械化证明

本文给出一种用高阶逻辑自动证明语言Isabelle在计算机中表示拓扑空间中开集、闭集、邻域和导集等基本概念的方法,在此基础上证明点集拓扑学中著名的杨忠道定理,即一拓扑空间的任意单点集的导集为闭集,则其任意子集的导集亦为闭集.

滇金丝猴粪便微生物来源的β-半乳糖苷酶基因的表达及酶学性质

[目的]对滇金丝猴粪便微生物来源的β-半乳糖苷酶进行异源表达和纯化,并研究其酶学性质。[方法]从滇金丝猴粪便微生物的宏基因组中克隆出一个β-半乳糖苷酶基因galRBM20_1,对该基因进行异源表达和酶学性质分析。构建含有T7强启动子的pEASY-E2-galRBM20_1质粒,转化至大肠杆菌BL21(DE3),经IPTG诱导表达后进行酶学性质研究。[结果]滇金丝猴粪便来源的β-半乳糖苷酶(galRBM20_1)最适pH为5.0,在pH 4-7之间能保留70%及其以上的活性。最适温度为45℃,在37℃和45℃下耐受1 h,酶活不变。特别的是,该酶具有良好的NaCl稳定性,经1-5 mol/L的NaCl作用1 h后,相对酶活均能超过初始酶活:当NaCl的作用浓度为4 mol/L时,β-半乳糖苷酶相对酶活最高(146%);当NaCl的作用浓度为5 mol/L时,β-半乳糖苷酶的相对酶活仍达到135%。[结论]本研究从滇金丝猴粪便微生物的宏基因库中克隆得到β-半乳糖苷酶基因galRBM20_1,并成功在大肠杆菌BL21(DE3)表达,首次从动物胃肠道宏基因组中获得具有耐盐和转糖基产Galactooligosaccharides(GOS)性能的β-半乳糖苷酶。该酶具有良好的耐盐性,和较广的pH作用范围,使其在食品、生物技术领域和环保方面的发展具有良好的应用价值。

Sin1/mTORC2 regulate B cell growth and metabolism by activating mTORC1 and Myc

Proper control of B cell growth and metabolism is crucial for B-cell-mediated immunity,but the underlying molecular mechanisms remain incompletely understood.In this study,Sin1,a key component of mTOR complex 2(mTORC2),specifically regulates B cell growth and metabolism.Genetic ablation of Sin1 in B cells reduces the cell size at either the transitional stage or upon antigen stimulation and severely impairs metabolism.Sin1 deficiency also severely impairs B-cell proliferation,antibody responses,and anti-viral immunity.At the molecular level,Sin1 controls the expression and stability of the c-Myc protein and maintains the activity of mTORC1 through the Akt-dependent inactivation of GSK3 and TSC1/2,respectively.Therefore,our study reveals a novel and specific role for Sin1 in coordinating the activation of mTORC2 and mTORC1 to control B cell growth and metabolism.

Layered material GeSe and vertical GeSe/MoS2 p-n heterojunctions

GroupqV monochalcogenides are emerging as a new class of layered materials beyond graphene, transition metal dichalcogenides （TMDCs）, and black phosphorus （BP）. In this paper, we report experimental and theoretical investigations of the band structure and transport properties of GeSe and its heterostructures. We find that GeSe exhibits a markedly anisotropic electronic transport, with maximum conductance along the armchair direction. Density functional theory calculations reveal that the effective mass is 2.7 times larger along the zigzag direction than the armchair direction; this mass anisotropy explains the observed anisotropic conductance. The crystallographic orientation of GeSe is confirmed by angle- resolved polarized Raman measurements, which are further supported by calculated Raman tensors for the orthorhombic structure. Novel GeSeflVIoS2 p-n heterojunctions are fabricated, combining the natural p-type doping in GeSe and n-type doping in MoS2. The temperature dependence of the measured junction current reveals that GeSe and MoS2 have a type-II band alignment with a conduction band offset of N 0.234 eV. The anisotropic conductance of GeSe may enable the development of new electronic and optoelectronic devices, such as high-efficiency thermoelectric devices and plasmonic devices with resonance frequency continuously tunable through light polarization direction. The unique GeSe/MoS2 p-n junctions with type-II alignment may become essential building blocks of vertical tunneling field-effect transistors for low-power applications. The novel p-type layered material GeSe can also be combined with n-type TMDCs to form heterogeneous complementary metal oxide semiconductor （CMOS） circuits.

Proving total correctness and generating preconditions for loop programs via symbolic-numeric computation methods

我们在场一个符号数字的混合方法，基于 sum-of-squares (求救) 松驰和合理向量恢复，为证明正确性全部并且为程序产生前提计算不平等 invariants 和评价函数。求救松驰方法被用来计算近似 invariants 并且接近与浮点系数评价功能。然后，高斯牛顿精炼和合理向量恢复被用于近似多项式与合理系数获得候选人多项式，它确切满足 invariants 的条件，评价工作。最后，几个例子被给显示出我们的方法的有效性。