From the Cover: The skeleton of tropical intraseasonal oscillations

The Madden–Julian oscillation (MJO) is the dominant mode of variability in the tropical atmosphere on intraseasonal timescales and planetary spatial scales. Despite the primary importance of the MJO and the decades of research progress since its original discovery, a generally accepted theory for its essential mechanisms has remained elusive. Here, we present a minimal dynamical model for the MJO that recovers robustly its fundamental features (i.e., its “skeleton”) on intraseasonal/planetary scales: (i) the peculiar dispersion relation of dω/dk ≈ 0, (ii) the slow phase speed of ≈5 m/s, and (iii) the horizontal quadrupole vortex structure. This is accomplished here in a model that is neutrally stable on planetary scales; i.e., it is tacitly assumed that the primary instabilities occur on synoptic scales. The key premise of the model is that modulations of synoptic scale wave activity are induced by low-level moisture preconditioning on planetary scales, and they drive the “skeleton” of the MJO through modulated heating. The “muscle” of the MJO—including tilts, vertical structure, etc.—is contributed by other potential upscale transport effects from the synoptic scales.     

牛卵丘细胞的生长特征与转基因

目的了解牛卵丘细胞的生长特征及构建的基因载体对卵丘细胞的转染情况和转染后阳性细胞的扩增效率。方法用透明质酸酶消化牛卵丘/卵母细胞复合体(COCs)获得牛卵丘细胞,了解牛卵丘细胞的生长特点,并用分子大小分别为7178 bp和31 085 bp两种带有增强绿色荧光蛋白(EGFP)和新霉素抗性基因(Neor)的质粒载体pMSCV-EGFP-Neor和pGC1-collagen-EGFP-Neor分别转染靶细胞。结果用脂质体法转染对数生长期的细胞,均获得了绿色荧光阳性细胞,但小质粒的转染效率在72 h时是大质粒的6倍(14%vs.2.3%)。在800μg/mLG418筛选浓度下,14 d后分别获得了7个和3个较明显的单克隆细胞群,对它们进行挑选、扩大,都获得了较纯的单克隆细胞系。最后根据EGFP和collagen的已知基因序列对转染pGC1-collagen-EGFP-Neor质粒的阳性细胞进行三个不同区域DNA片段的扩增,结果表明,扩增的基因片段大小正确,数目完整。结论对卵丘细胞进行基因转染,分子大小等于或小于31 kb的基因可以有效转入,但小分子载体比大分子载体具有更高的转染效率。经过筛选都可以获得纯的转基因细胞...     

Incomplete denudation of oocytes prior to ICSI enhances embryo quality and blastocyst development

BACKGROUND: Granulosa cells are essential mediators of oocyte maturation and fertilization. Because of the denudation of oocytes in preparation for ICSI, any potential positive effect of surplus cumulus cells (CCs) on further development would be unable to exert further effect. In order to evaluate the actual influence of adhering cumulus cells on further preimplantation development, this prospective study was carried out. METHODS: Sibling cumulus-oocyte complexes for 57 ICSI patients were split into a study group (incomplete denudation, n = 314) and a control group (complete denudation, n = 336). According to the cumulus cell pattern after partial denudation, mature gametes from the study group were further subdivided into type A oocytes, which showed several prominent CC clusters (n = 202), and type B (n = 75), which showed a more homogeneous pattern with CC covering the whole surface of the gamete. RESULTS: In immature oocytes, presence of adhered CCs led to a significant increase in resumption of meiosis (P < 0.01). Fertilization rate (P < 0.05) and ability to cleave (P < 0.01) was impaired in the study group, because of difficulties in ICSI of type B oocytes. By contrast, embryo morphology on days 2 (P < 0.01) and 3 (P < 0.05), as well as blastocyst formation, was better (P < 0.05) in the study group (55 blastocysts out of 88 zygotes) as compared to that in the control group (49/105). CONCLUSION: These data indicate that co-culture of oocytes with attached CCs may enhance preimplantation development.     

Transport kinetics of four- and six-coordinate platinum compounds in the multicell layer tumour model

Four-coordinate (Pt(II)) platinum-based anticancer drugs are widely used in primary or palliative chemotherapy and produce considerable efficacy in certain clinical applications, for example testicular cancer. However, in many cancers the Pt(II) drugs are beset by poor efficacy mainly due to suboptimal pharmacokinetic properties. Consequently, the six-coordinate (Pt(IV)) class of Pt drugs were developed to improve platinum efficacy by (i) increasing stability, (ii) reducing reactivity, (iii) increasing lipophilicity, and (iv) nuclear targeting. However, comparatively little information is available on the pharmacokinetic properties of these compounds within solid tumour tissue. In the present study, the distribution and fluxes of [(14)C]-labelled [PtCl(2)(en)] (where en stands for ethane-1,2-diamine) and cis,trans-[PtCl(2)(OH)(2)(en)] drugs were determined in the multicell layer (MCL) tumour model comprising colon cancer cells. Flux data were analysed by mathematical modelling of drug diffusion and cellular uptake in the transport system. The flux of the Pt(IV) compound through the MCL was not significantly different to that of the Pt(II) drug nor were the diffusion coefficient or tissue uptake; the latter confirmed with elemental imaging analysis by synchrotron radiation induced X-ray emission. However, the flux of the Pt(IV) through the MCL was increased by hydrostatic pressure, thereby demonstrating the potential to target cancer cells further away from the vessels with six-coordinate platinum drugs.     

Development of a guideline for the water bolus temperature in superficial hyperthermia

Purpose: The research presented in this work investigates the influence of the water bolus temperature on temperature distributions in tissue during superficial hyperthermia treatments using Lucite cone applicators. The goal of the research was to develop a guideline for the selection of the water bolus temperature based on 3-D electromagnetic and thermal modelling.

Methods: A 3-D model was set up to simulate an abstraction of the treatment. In the model a convection coefficient for the water bolus to skin surface was employed. In order to simulate the heat balance as realistically as possible, convection coefficients were measured for different water boluses and ranged from 70–152?W (m²?K)^?1. The model was evaluated by simulating three clinical treatments and comparing the outcome of the model to the clinical measurements.

Results: The model was found to predict the temperature distribution well on a global view; root mean square errors between 0.66–1.5°C were found for the three treatments. For some temperature probes a deviation of 1.5–2.0°C between measured and predicted temperature was found. These large deviations can be explained by local variations in cooling by blood vessels, tissue inhomogeneity, a varying convection coefficient of the water bolus and of course the complexity of the anatomy.

Conclusions: The model was used to set up guidelines for the water bolus temperature selection in clinical practice for the target depths and applicator arrays used in the Rotterdam Erasmus Medical Center.     

卵母细胞分泌因子在人卵丘颗粒细胞中的表达及其与卵母细胞发育潜能的关系

目的:探讨单卵母细胞所对应的卵丘颗粒细胞(cumulus cells,CCs)中生长分化因子-9(GDF-9)、骨形成蛋白-15(BMP-15)、转化生长因子β1(TGFβ1)、Smad3的表达与对应单卵母细胞质量及其发育潜能的关系以及在不同促排卵方案中的表达。方法:因男方因素或曾有过体外受精(IVF)不受精史接受卵胞质内单精子显微注射(ICSI)治疗的患者41例,单卵母细胞的CCs 332份(Gn RH-a组21例172份CCs,非垂体降调节组20例160份CCs)。拣卵后机械法剥离单卵子周围的CCs,将卵母细胞与收集的CCs一一对应进行分析。M_Ⅱ卵均采用ICSI授精,并观察其受精、卵裂及囊胚发育情况。采用Real-time PCR方法检测,比较各组CCs中GDF-9、BMP-15、TGFβ1和Smad3的相对含量。结果:1 CCs收集及PCR扩增产物可满足实验要求。2 Gn RH-a组及非垂体降调节组中,上述4种卵母细胞分泌因子,在正常受精组的相对含量均显著高于异常受精组;优质卵裂胚形成组的相对含量均显著高于非优质卵裂胚形成组;优质囊胚形成组中的相对含量显著高于非优质囊胚形成组。3 Gn RH-a组的CCs中BMP-15的表达量相对更高;而GDF-9、TGFβ1和Smad3在非降调节组的CCs中相对表达量较高。结论:1采用单卵母细胞的CCs的RNA进行研究,实际操作是可行的,RNA的质量和数量可达到实验要求。2 GDF-9、BMP-15、TGFβ1、Smad3可作为评价卵母细胞质量、预测卵母细胞发育潜能的客观指标。3降调节与否可能影响CCs中的卵母细胞分泌因子的表达水平,且与M_Ⅱ期卵母细胞发育潜能有关。     

人卵丘细胞 lncRNA ENST00000502521的表达与胚胎发育的关系

目的：探讨体外受精(IVF)周期人卵丘细胞(CCs)中lncRNA ENST00000502521的表达与卵母细胞成熟及胚胎发育的关系,判断其对体外受精-胚胎移植(IVF-ET)结局的预测价值。方法收集40例首次接受长方案超促排卵患者的卵丘细胞,根据卵丘细胞围绕的卵母细胞受精后胚胎发育情况将卵丘细胞分成两组,优质胚胎组和低质胚胎组,采用实时荧光定量逆转录-聚合酶链反应(qRT-PCR)技术检测两组卵丘细胞中 lncRNA ENST00000502521的相对表达量,分析其与胚胎发育及妊娠结局的关系;采用受试者工作特征曲线(ROC)评价 lncRNA ENST00000502521相对表达量对临床妊娠结局的预测价值。结果 IVF 患者低质胚胎组中 ln-cRNA ENST0000050252表达较优质胚胎组明显增高( P <0．05),且未妊娠组 lncRNA ENST00000502521相对表达量较妊娠组增高(P <0．05);lncRNA ENST00000502521预测妊娠结局的 ROC 曲线下面积(AUC)为0．71(P <0．05,95% CI：0．55~0．87),灵敏度为84．2%,特异性为61．9%。结论lncRNA ENST00000502521可能参与影响卵母细胞成熟及胚胎发育,可作为一个潜在的分子标志物预测胚胎质量和妊娠结局。     

A globally fragmented and mobile lithosphere on Venus

Venus has been thought to possess a globally continuous lithosphere, in contrast to the mosaic of mobile tectonic plates that characterizes Earth. However, the Venus surface has been extensively deformed, and convection of the underlying mantle, possibly acting in concert with a low-strength lower crust, has been suggested as a source of some surface horizontal strains. The extent of surface mobility on Venus driven by mantle convection, however, and the style and scale of its tectonic expression have been unclear. We report a globally distributed set of crustal blocks in the Venus lowlands that show evidence for having rotated and/or moved laterally relative to one another, akin to jostling pack ice. At least some of this deformation on Venus postdates the emplacement of the locally youngest plains materials. Lithospheric stresses calculated from interior viscous flow models consistent with long-wavelength gravity and topography are sufficient to drive brittle failure in the upper Venus crust in all areas where these blocks are present, confirming that interior convective motion can provide a mechanism for driving deformation at the surface. The limited but widespread lithospheric mobility of Venus, in marked contrast to the tectonic styles indicative of a static lithosphere on Mercury, the Moon, and Mars, may offer parallels to interior–surface coupling on the early Earth, when global heat flux was substantially higher, and the lithosphere generally thinner, than today.

Despite close similarities in mass and bulk composition, Earth and Venus have followed different evolutionary paths, at least over recent Solar System history (1). Given the detection of ever more Earth-mass extrasolar planets at distances from their host stars in the so-called “Venus zone” (2), it is increasingly important to understand the geological character and history of our nearest planetary neighbor. Observations of the planet’s cratering record and inferences about its volcanic history led to the view that Venus exists either in a stagnant lid (3) or episodic lid (4) tectonic regime, which differ mainly in terms of rates of volcanic and tectonic activity. In any case, with a lithosphere coupled to a highly viscous asthenospheric mantle and inhibited from major lateral motion, by this view, Venus has likely behaved as a one-plate planet for at least the last 0.5–1 billion years (5, 6).However, this perspective is challenged by geological observations of deformation indicative of lateral motions—both isolated instances within the planet’s lowlands (7–9) and on a much greater horizontal scale in the vicinity of Lakshmi Planum, which appears to have collided as a block with Ishtar Terra (10), and regional transcurrent shear zones >1,000 km long between Ovda and Thetis Regiones (10, 11). Additionally, recent efforts to reconcile geological and geophysical observations of Venus (12) invoke an active, steady-state interior maintained by recycling of the mantle portion of the lithospheric lid (13), and even localized lithospheric subduction outward of sites of major mantle upwelling (14, 15). Further, although Venus shows no evidence of Earth-like tectonic plates today, mantle convection might drive some horizontal motion and associated surface deformation (10, 11, 16–18), possibly facilitated by a weak lower crustal layer arising from the planet’s currently high surface temperature (∼740 K) (13, 19, 20).     

Irregular topography at the Earth's inner core boundary

Compressional seismic wave reflected off the Earth’s inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth’s ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4–8 km with a lateral length scale of 2–4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable.