第十八届美国理论与应用力学大会总结

1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学

The Chlorophyll-a Distribution of Yantai Coastal Waters Based on MODIS Data

利用实测光谱数据及水体叶绿素浓度数据建立了基于MODIS数据的叶绿素反演模型,并利用MODIS L1B数据对研究区的叶绿素浓度进行了反演。通过分析烟台近海水体叶绿素浓度分布得出,烟台近海水体叶绿素浓度由沿岸向海延伸,叶绿素的浓度逐渐增加;通过不同月份的叶绿素浓度分布状况发现,夏季水体叶绿素浓度含量最高,冬季最低

The analysis of NDVI trends in the coastal zone based on Mann-Kendall test：a case in the Jiaodong Peninsula

利用1998—2008年SPOT/VEGETATION逐旬共372期归一化植被指数时间序列影像数据,引入Mann-Kendall非参数趋势检验方法,分析了胶东半岛最近10 a来的归一化植被指数变化趋势。结果表明,最近10 a来,胶东半岛归一化植被指数变化趋势以衰减区域居主导地位,其中有明显衰减变化趋势的区域占半岛总面积的19.3%,有明显增强变化趋势的区域仅占半岛总面积的2.8%。归一化植被指数衰减区域在空间上沿海岸线呈环状分布,从沿海岸到远离海岸,归一化植被指数增强趋势逐渐明显,衰减最明显的区域大部分位于半岛沿海30 km以内,植被增强趋势最明显区域位于半岛中部山地及沿海防护林地区。人类活动及其空间分布是归一化植被指数变化的主要因素,其中沿海城市化、工业化和海岸湿地开发利用程度的提高导致归一化植被指数衰减,而山地植被保护和海岸防护林建设导致归一化植被指数增强

Diffusion of rod-like nanoparticles in non-adhesive and adhesive porous polymeric gels

It is known that rod-like nanoparticles (NPs) can achieve higher diffusivity than their spherical counterparts in biological porous media such as mucus and tumor interstitial matrix, but the underlying mechanisms still remain elusive. Here, we present a joint experimental and theoretical study to show that the aspect ratio (AR) of NPs and their adhesive interactions with the host medium play key roles in such anomalous diffusion behaviors of nanorods. In an adhesive polymer solution/gel (e.g., mucus), hopping diffusion enables nanorods to achieve higher diffusivity than spherical NPs with diameters equal to the minor axis of the rods, and there exists an optimal AR that leads to maximum diffusivity. In contrast, the diffusivity of nanorods decreases monotonically with increasing AR in a non-adhesive polymer solution/gel (e.g., hydroxyethyl cellulose, HEC). Our theoretical model, which captures all the experimental observations, generalizes the so-called obstruction scaling model by incorporating the effects of the NPs/matrix interaction via the mean first passage time (MFPT) theory. This work reveals the physical origin of the anomalous diffusion behaviors of rod-like NPs in biological gels and may provide guidelines for a range of applications that involve NPs diffusion in complex porous media. (C) 2018 Elsevier Ltd. All rights reserved

重离子辐照冬小麦诱变效应的研究

利用3.2—75MeV/u4个能量、2×108—12×108cm–24个剂量的O和C重离子处理3个冬小麦品种,1612研究其诱变效应。结果表明,M1代的生物损伤随剂量的增加而加大;8MeV/u能量的损伤要比高能75MeV/u时大;8MeV/u较易出现在高能75MeV/u离子和γ辐射中未见的条状叶绿素缺失损伤,此结果未见相关报导。M2代诱变效果显著,突变谱宽,有益突变(早熟、矮杆、穗形)频率明显高于γ射线,且较易诱发早抽穗性状变异

Over-expression of PC-1 Gene Increases Survival Ability of C4-2B Prostate Cancer Cell Line

建立稳定表达外源PC-1基因的人前列腺癌骨转移C4-2B细胞模型,初步探讨PC-1基因表达对前列腺癌发展的影响.通过脂质体介导的方法,将融合PC-1基因的真核表达载体pcDNA3·1-PC-1稳定转染C4-2B细胞,Western印迹和RT-PCR技术,分别从蛋白水平和RNA水平确定外源PC-1基因表达.MTT和软琼脂集落形成能力等一系列方法,研究PC-1基因的功能,RT-PCR和实时定量PCR检测前列腺癌发生发展相关基因表达的变化.结果表明,PC-1基因的高表达能够诱导雄激素受体(AR)调控基因和一系列重要的信号通路成员基因PSA、PSMA、NKX3·1、Jagged1、EphA3、SGEF和NOTCH3等表达发生变化.实验结果初步证明,PC-1基因表达在晚期前列腺癌中,以及在雄激素非依赖的转变中可以发挥作用,PC-1基因表达可调控一些重要信号通路.对PC-1基因功能深入研究将有可能为发现新的前列腺癌的诊断治疗分子靶标提供线索.To investigate the potential role of PC-1 gene over-expression on prostate cancer progression, a metastasis and androgen independent prostate cancer cell line C4-2B was used, cell clones constitutively expressing PC-1, and their mock-transfected counterparts were constructed. The expression of ectopic PC-1 was analyzed by Western blot and RT-PCR assay. MTT and colony anchor-independent growth in soft agar were performed to evaluate the effects of PC-1 gene expression on prostate cancer progression. RT-PCR and real-time PCR were used to analyse the expression of differential genes between C4-2B-PC-1 and C4-2B-neo cell lines. Our results showed that stable expression PC-1 induced transcription change of some genes, including PSA,PSMA,NKX3.1,Jagged1, EphA3, SGEF and NOTCH3, which were the androgen receptor, regulated genes and important signal transduction pathway molecules. These observations indicated that PC-1 over-expression might play important role in advanced prostate cancer progression, promote prostate cancer cell androgen independent growth, and may regulate multiple signal transduction pathways. Further study of PC-1 gene function may provide clue to discover new molecular targets for prostate cancer diagnosis and treatment.国家自然科学基金资助(No.30070296)~

Molecular Cloning and Characterization of a Putative Promoter Region of mPC-1 Gene Homologous to hPC-1

为了鉴定鼠mPC-1基因表达的调控元件,克隆并分析了该基因的启动子.构建了一系列mPC-1基因启动子的截短序列.通过荧光素酶报道基因,分析了它们在前列腺癌细胞和其它细胞中的表达.结果表明,在AR阳性细胞系中,mPC-1基因启动子活性远远高于SV40和p61-PSA启动子,mPC-1基因启动子599bp至449bp可能含有一个负调控元件;mPC-11.1kb启动子控制的表达主要在前列腺癌细胞系中;雄激素可调控mPC-11.1kb启动子表达.mPC-11.1kb序列是一个有前列腺癌细胞特异性和较强的启动子,经过进一步的修饰有可能作为一种有用的前列腺癌基因治疗元件.To identify the regulatory region that are responsible for the expression of mPC-1,we have isolated and characterized the mPC-1 gene promoter.Sequence analysis of the mPC-1 5'-flanking region and a series of truncated constructs were performed,which were transiently transfected into the prostate cancer cell lines and non-prostate cancer cell lines and analyzed through Dual-luciferase reporter assay system.The relative activity of mPC-1 gene promoter was by far higher than pGL3-control containing SV40 promoter and enhancer and p61-PSA containing hPSA 6 kb promoter in AR(androgen receptor,AR)-positive prostate cancer cell lines.The region from 599 bp to 449 bp of mPC-1 promoter might contain a negative regulatory element.The expression of mPC-1 1.1 kb fragment is mainly restricted into prostate cancer cell lines.The relative activity of mPC-1 1.1 kb 5'-flanking region was regulated by androgen.The results demonstrated that the 1.1 kb fragment of mPC-1 5'-flanking region was relatively strong and prostate cancer cell specific promoter region.The 1.1 kb promoter of mPC-1 gene might be well suited to prostate cancer gene therapy if the promoter was properly modified.国家高技术研究发展计划(863计划)(No.2002AA223061);; 国家自然科学基金(No.30070296)资助~

Effects of graphene oxide nanosheets on the ultrastructure and biophysical properties of the pulmonary surfactant film

Graphene oxide (GO) is the most common derivative of graphene and has been used in a large range of biomedical applications. Despite considerable progress in understanding its cytotoxicity, its potential inhalation toxicity is still largely unknown. As the pulmonary surfactant (PS) film is the first line of host defense, interaction with the PS film determines the fate of the inhaled nanomaterials and their potential toxicity. Using a coarse-grained molecular dynamics model, we reported, for the first time, a novel mechanism of toxicity caused by the inhaled GO nanosheets. Upon deposition, the GO nanosheets induce pores in the PS film and thus have adverse effects on the ultrastructure and biophysical properties of the PS film. Notably, the pores induced by GO nanosheets result in increasing the compressibility of the PS film, which is an important indication of surfactant inhibition. In vitro experiments have also been conducted to study the interactions between GO and animal-derived natural PS films, qualitatively confirming the simulation results

Physicochemical properties of nanoparticles regulate translocation across pulmonary surfactant monolayer and formation of lipoprotein corona

Interaction with the pulmonary surfactant film, being the first line of host defense, represents the initial bio-nano interaction in the lungs. Such interaction determines the fate of the inhaled nanoparticles and their potential therapeutic or toxicological effect. Despite considerable progress in optimizing physicochemical properties of nanoparticles for improved delivery and targeting, the mechanisms by which inhaled nanoparticles interact with the pulmonary surfactant film are still largely unknown. Here, using combined in vitro and in silico methods, we show how hydrophobicity and surface charge of nanoparticles differentially regulate the translocation and interaction with the pulmonary surfactant film. While hydrophilic nanoparticles generally translocate quickly across the pulmonary surfactant film, a significant portion of hydrophobic nanoparticles are trapped by the surfactant film and encapsulated in lipid protrusions upon film compression. Our results support a novel model of pulmonary surfactant lipoprotein corona associated with inhaled nanoparticles of different physicochemical properties. Our data suggest that the study of pulmonary nanotoxicology and nanoparticle-based pulmonary drug delivery should consider this lipoprotein corona

A microfluidic tubing method and its application for controlled synthesis of polymeric nanoparticles

This report describes a straightforward but robust tubing method for connecting polydimethylsiloxane (PDMS) microfluidic devices to external equipment. The interconnection is irreversible and can sustain a pressure of up to 4.5 MPa that is characterized experimentally and theoretically. To demonstrate applications of this high-pressure tubing technique, we fabricate a semicircular microfluidic channel to implement a high-throughput, size-controlled synthesis of poly(lactic-co-glycolic acid) (PLGA) nanoparticles ranging from 55 to 135 nm in diameter. This microfluidic device allows for a total flow rate of 410 mL h(-1), resulting in enhanced convective mixing which can be utilized to precipitate small size nanoparticles with a good dispersion. We expect that this tubing technique would be widely used in microfluidic chips for nanoparticle synthesis, cell manipulation, and potentially nanofluidic applications