3D microgel with extensively adjustable stiffness and homogeneous microstructure for metastasis analysis of solid tumor

3D microgels with various mechanical properties have been important platforms tumor metastasis analysis, and widely adjustable stiffness is crucial for deeper researches. Herein, by mixing biodegradable polylactic acid (PLA) nanofibers in the modified alginate with different concentrations of Ca²⁺, we significantly enhance the stiffness range of microgels while retaining the pore size, which provides bionic microenvironment for tumor analysis. As a proof of concept, we simulated the mechanical characteristics of breast tumors by encapsulating cells in 3D microgels with diverse stiffness, and analyzed cellular behaviors of two typical breast cancer cell lines: MCF-7 and SUM-159. Results showed that with the addition of 2.0% (w/v) PLA short nanofibers, the Young's modulus of modified alginate increased more than three-fold. Besides preserving high survival and proliferation rates, both cells also displayed stronger migration ability in soft microgel spheres, where RT-qPCR analysis revealed the underlying changes at the genetic level. This systematic study demonstrated our method is powerful for creating widely adjustable 3D mechanical microenvironment, and the results of cellular behavior analysis shows its promising application prospects in tumorigenesis and progression.     

The progress and perspective of strategies to improve tumor penetration of nanomedicines

Tumor penetration is important fo r effectively tumor targeting drug delivery.Recently,many researches are published to overcome the barriers that restrict tumor penetration and improve drug delivery efficiency.In the mini review,we first analyzed the barriers influence the tumor penetration,including tumor microenvironment barriers,nanoparticle properties,and interaction barriers between tumor and nanoparticles.To overcome the barrier,several strategies are developed,including modulating tumor microenvironment,changing particle size,transcytosis enabled tumor penetration,cell penetrating peptide modification and overcoming binding site barrier,which could effectively improve tumor penetration,and finally enhance tumor treatment outcome.     

Electrochemical detection of quantum dots by stabilization of electrogenerated copper species

The determination of quantum dots is of particular interest as they are frequently used as labels in electrochemical biosensors. In this paper, we describe a method for the detection of very low concentrations of quantum dots using the voltammetric response of copper in ammonia solution. Copper species electrogenerated on the electrode surface are stabilized by the nanoparticles, preventing their oxidation by dissolved oxygen, and a relationship between the concentration of the nanoparticles and the copper voltammetric response can thus be obtained. The reported method shows a linear range between 0.05 and 2 nM of quantum dots, with a limit of detection in the order of 9 × 10⁷ nanoparticles. This method could be employed to improve the detection limit of electrochemical biosensors using quantum dots as labels.     

Recent research and development of DYRK1A inhibitors

Dual specificity tyrosine phosphorylation regulated kinase 1 A(DYRK1 A) is an evolutionarily conserved protein kinase belonging to the CMGC kinase family, which is closely related to Down syndrome(DS)and Alzheimer’s disease(AD). In recent years, not only the treatment of diabetes, but also the treatment of cancer gradually focuses on targeting DYRK1 A. Therefore, a series of DYRK1 A inhibitors have been developed to treat relevant diseases and clarify their treatment mechanism furtherly. DYRK1 A...     

瀑布沟水电站库首右岸深部裂缝成因分析

水电工程常常建在高山峡谷地带,其天然岸坡通常由坡面向内有一个强卸荷带和弱卸荷带以及相应的强风化和弱风化带,内侧则为完整新鲜的岩石。对涉及的工程岸坡在正常卸荷带以内发育的一系列张性破裂或破裂带,称之为“深拉裂缝”。瀑布沟水电站库首右岸存在两个拉裂变形体,通过对其岸坡深部拉裂缝空间发育分布、变形特征的考察,综合分析造成深部裂缝发育规律与变形特征的因素。在此基础上提出,库首右岸深部拉裂缝是岸坡快速卸荷条件下浅表生改造的产物,其形成时期相当于河谷由宽谷深切为峡谷这一转换时期。     

Cationic dirhodium carboxylate-catalyzed synthesis of dihydropyrimidones from propargyl ureas

Cationic Rh(II) complexes are able to catalyze the regioselective hydroamination of propargyl ureas in a 6-endo fashion. This transformation permits access to interesting substitution patterns of dihydropyrimidines, which have found use as nucleotide exchange factor inhibitors.     

Early transient responses of multi-span stepped single-walled carbon nanotubes using the method of reverberation ray matrix

The early transient responses of multi-span stepped single walled carbon nanotubes (SWCNTs) under impact loadings are studied by the method of reverberation ray matrix (MRRM). The dynamics model of the carbon nanotubes is established in the Fourier phase space on the basis of the nonlocal Timoshenko beam model. The wave solutions of SWCNTs with arbitrary boundary conditions are obtained by the wave method. The reverberation ray matrix of the multi-span stepped SWCNTs is the product of scattering, phase and permutation matrices, which can be determined by the impact loadings, continuous conditions and boundary conditions. The early transient responses can be calculated by the inverse Fourier transform of the sum of initial ray groups. It can be found that the early transient displacement response in the very short time subjected to the impact loading is very small, while the transient transverse shear strain becomes large in the very short time. The influences of nanotubes span number, nanotubes type and boundary conditions on the early transient responses of multi-span stepped SWCNTs are investigated.     

反相高效液相色谱法测定血浆中的单硝酸异山梨酯

建立了反相高效液相色谱测定血浆中单硝酸异山梨酯浓度的方法。样品在碱性条件下经二氯甲烷提取后,用C18柱进行分离,以H2O(用0.03 mol/L氨水调pH至7.8)-乙腈(体积比为80∶20)为流动相,对乙酰氨基酚为内标,于230 nm处测定。结果表明,单硝酸异山梨酯的质量浓度为20~1000 μg/L时其峰面积与内标峰面积之比与单硝酸异山梨酯浓度有良好的线性关系。方法的最低检测质量浓度为12 μg/L,平均回收率为(97.11±2.45)％~(104.34±2.17)%,日内测定的相对标准偏差(RSD)≤2.52%,日间测定的RSD≤5.21%。     

对碎裂结构岩体似连续介质特征的一点研究

通常情况下认为碎裂结构的岩体具有非连续介质的特征。但是随着西部大量水电工程的勘查和建设,遇到了一类比较特殊的岩体,这类岩体中裂隙发育,结构面间距很小,按照国标划分为碎裂结构岩体,但是其本身又具有较高的力学性质,表现为具有较高的变形模量、抗剪强度参数和完整性系数,并且具有似连续介质的特征,这与通常的碎裂结构岩体有本质的区别。本文将利用两个实例工程对这一现象进行初步的分析,得到了水电工程可利用岩体的一种新的评价方法。