Numerical simulation of two-phase non-Newtonian blood flow with fluid-structure interaction in aortic dissection

The behavior of blood cells and vessel compliance significantly influence hemodynamic parameters, which are closely related to the development of aortic dissection. Here the two-phase non-Newtonian model and the fluid-structure interaction (FSI) method are coupled to simulate blood flow in a patient-specific dissected aorta. Moreover, three-element Windkessel model is applied to reproduce physiological pressure waves. Important hemodynamic indicators, such as the spatial distribution of red blood cells (RBCs) and vessel wall displacement, which greatly influence the hemodynamic characteristics are analyzed. Results show that the proximal false lumen near the entry tear appears to be a vortex zone with a relatively lower volume fraction of RBCs, a low time-averaged wall shear stress (TAWSS) and a high oscillatory shear index (OSI), providing a suitable physical environment for the formation of atherosclerosis. The highest TAWSS is located in the narrow area of the distal true lumen which might cause further dilation. TAWSS distributions in the FSI model and the rigid wall model show similar trend, while there is a significant difference for the OSI distributions. We suggest that an integrated model is essential to simulate blood flow in a more realistic physiological environment with the ultimate aim of guiding clinical treatment.     

太子参花药发育及精细胞分离

太子参花药壁发育为基本型,腺质绒毡层。小孢子母细胞减数分裂为同时型,小孢子四分体为四面体型,成熟花粉具两个精细胞,为3胞花粉。在花粉表面具散孔,孔数22—30个,均匀分布于花粉粒表面上。花粉在10％甘露醇或15％蔗糖溶液中可直接爆破,精细胞易被释放并散开,通过显微操作仪可收集到一定数目的精细胞。FDA染色荧光显示释放出来的精细胞活力可维持25—50min。花粉在舍O．03％CaCl2、0．01％H3803、0．01％KH2P04和20％PEG、pH5．8的培养液中2—5min即萌发花粉管．花粉管生长2h可达815μm。一般花粉管伸长500—600μm时,一对精细胞才进入花粉管。DAPI染色后荧光观察．可观察到精细胞和营养细胞核在花粉管中的移动状况。爆破花粉管后可释放出一对精细胞。     

洋葱花粉发育过程中ATP酶的分布特征(简报)

在真核细胞中,除了线粒体和叶绿体ATPase的功能是合成ATP外,其余部位ATPase是水解ATP以获取生物能量的代谢酶,在生物体细胞内广泛存在。探索ATPase在细胞中的分布状态是研究细胞生理状态的一种重要手段。ATPase在细胞中的多少可反映出细胞当时的生活状态,这一特征已被初步用于探索小麦和水稻雄性不育的细胞生物学研究中,希望通过比较可育花药和不育花药中ATPase的分布差异寻找雄性不育的机理,发现     

Specific on-plate enrichment of phosphorylated peptides for direct MALDI-TOF MS analysis

An on-plate specific enrichment method is presented for the direct analysis of peptides phosphorylation. An array of sintered TiO 2 nanoparticle spots was prepared on a stainless steel plate to provide porous substrate with a very large specific surface and durable functions. These spots were used to selectively capture phosphorylated peptides from peptide mixtures, and the immobilized phosphopeptides could then be analyzed directly by MALDI MS after washing away the nonphosphorylated peptides. beta-Casein and protein mixtures were employed as model samples to investigate the selection efficiency. In this strategy, the steps of phosphopeptide capture, purification, and subsequent mass spectrometry analysis are all successfully accomplished on a single target plate, which greatly reduces sample loss and simplifies analytical procedures. The low detection limit, small sample size, and rapid selective entrapment show that this on-plate strategy is promising for online enrichment of phosphopeptides, which is essential for the analysis of minute amount of samples in high-throughput proteome research.     

Bistability and oscillations in the Huang-Ferrell model of MAPK signaling

Physicochemical models of signaling pathways are characterized by high levels of structural and parametric uncertainty, reflecting both incomplete knowledge about signal transduction and the intrinsic variability of cellular processes. As a result, these models try to predict the dynamics of systems with tens or even hundreds of free parameters. At this level of uncertainty, model analysis should emphasize statistics of systems-level properties, rather than the detailed structure of solutions or boundaries separating different dynamic regimes. Based on the combination of random parameter search and continuation algorithms, we developed a methodology for the statistical analysis of mechanistic signaling models. In applying it to the well-studied MAPK cascade model, we discovered a large region of oscillations and explained their emergence from single-stage bistability. The surprising abundance of strongly nonlinear (oscillatory and bistable) input/output maps revealed by our analysis may be one of the reasons why the MAPK cascade in vivo is embedded in more complex regulatory structures. We argue that this type of analysis should accompany nonlinear multiparameter studies of stationary as well as transient features in network dynamics.     

Nitrogen-doped carbon dots as a fluorescent probe for the highly sensitive detection of bilirubin and cell imaging

Nitrogen-doped carbon dots (NCDs) with bright blue fluorescence were constructed by a hydrothermal method using sucrose and l- proline as raw materials. The NCDs were characterized by transmitted electron microscopy, X-ray diffraction, Fourier-transform infrared spectrometry, X-ray photoelectron spectroscopy, and ultraviolet-visible absorption and fluorescence spectroscopy to investigate the morphology, elemental composition, and optical properties. The NCDs had good water solubility, high dispersibility with an average diameter of only 1.7 nm, and satisfactory optical properties with a fluorescence quantum yield of 23.4%. The NCDs were employed for the detection of bilirubin. A good linear response of the NCDs in the range 0.35–9.78 μM was obtained for bilirubin with a detection limit of 33 nM. The NCDs were also applied to the analysis of real samples, serum and urine, with a recovery of 95.34% to 104.66%. The low cytotoxicity and good biocompatibility of the NCDs were indicated by an MTT assay and cell imaging of HeLa cells. Compared with other detection systems, using NCDs for bilirubin detection was a facile and efficient method with good selectivity and sensitivity.     

Mathematical modeling of shear-activated targeted nanoparticle drug delivery for the treatment of aortic diseases

Biomechanics and Modeling in Mechanobiology - The human aorta is a high-risk area for vascular diseases, which are commonly restored by thoracic endovascular aortic repair. In this paper, we report...     

HSV-1UL6基因编码门蛋白的结构及功能

门蛋白在单纯疱疹病毒1型（HSV-1）的衣壳装配和基因组包装过程中扮演重要角色,对病毒的复制有重要作用。本文就HSV-1 UL6基因编码的门蛋白进行阐述,具体介绍形成门蛋白多聚体的影响因素,门蛋白及其周边蛋白的结构及功能,以及其靶点药物的研究现状等,以期为研究门蛋白在疱疹病毒感染和复制过程中的作用提供一定参考。     

四川贡嘎山国家级自然保护区鸟兽多样性

四川贡嘎山国家级自然保护区位于全球生物多样性热点地区之一的横断山区, 是我国生物多样性保护优先区。本文利用红外相机影像和已发表文献对该保护区的大中型兽类和地面活动鸟类进行编目并提出未来监测建议。2011-2018年在97个1 km × 1 km的网格安放红外相机, 累计39,881个相机日, 获得独立有效照片20,932张, 其中野生兽类16,244张, 鸟类2,775张, 牲畜1,737张, 人176张。鉴定出野生兽类30种, 另有文献报道4种和观察3种, 分属于5目15科; 鸟类78种, 分属于9目22科; 牲畜6种。包括12种国家I级和28种国家II级重点保护野生动物; 被CITES附录I收录的有11种, 附录II收录的有12种。被IUCN红色名录评估为濒危(EN)和易危(VU)等级的分别有3种和8种。被《中国脊椎动物红色名录》评估为极危(CR)、濒危和易危等级的分别有5、5和11种。相对多度指数(relative abundance index, RAI)排名前三的兽类是毛冠鹿(Elaphodus cephalophus, 147.39)、水鹿(Rusa unicolor, 66.10)、野猪(Sus scrofa, 36.03); 鸟类是血雉(Ithaginis cruentus, 14.64)、白马鸡(Crossoptilon crossoptilon, 10.43)、大噪鹛(Garrulax maximus, 8.05)。阔叶林、针阔混交林、高山灌丛草甸和高山流石滩是调查薄弱生境, 后期应开展重点调查, 以厘清本区域大中型兽类资源。     

Exosomal microRNA-155-5p from PDLSCs regulated Th17/Treg balance by targeting sirtuin-1 in chronic periodontitis

The mechanism of local inflammation and systemic injury in chronic periodontitis is complicated, in which and exosomes play an important role. In our study, we found that T helper cell 17 (Th17)/regulatory T cell (Treg) balance is destabilized in the peripheral blood of patients with periodontitis, with upregulated Th17 or downregulated Treg, respectively. Porphyromonas gingivalis lipopolysaccharide (LPS) was used to simulate the inflammatory microenvironment of chronic periodontitis. The exosomes were extracted from periodontal ligament stem cells (PDLSCs) in LPS-induced periodontitis environment, which inversely effected on CD4+ T cells under normal and inflammatory conditions. Furthermore, compared with exosomes from normal PDLSCs, lower expression of microRNA-155-5p (miR-155-5p) and higher expression of Sirtuin-1 (SIRT1) were observed in exosomes from LPS-stimulated PDLSCs. Exosomes from PDLSCs alleviated inflammatory microenvironment through Th17/Treg/miR-155-5p/SIRT1 regulatory network. This study aimed to find the “switching” factors that affected the further deterioration of periodontitis to maximally control the multiple downstream damage signal factors to further understand periodontitis and find new targets for its treatment.