CfDNA-based liquid biopsy of cerebrospinal fluid in medulloblastoma

Medulloblastoma(MB)is the most common childhood embryonal malignant tumour in the central nervous system.The diagnosis,prognosis and therapeutic targets of MB depend on the molecular characteristics of the tumor,and it is a great challenge to obtain the tissue samples from the patients with brain tumor.Genomic changes found in cell-free DNA(cfDNA)of cerebrospinal fluid(CSF)can predict genomic changes present in tumor tissue,fluid biopsy of CSF can detect the genomic profile of tumor-associated cfDNA and evaluate cfDNA as a marker of measurable residual disease(MRD)in a relatively noninvasive manner,which provides the evidence of"individualized precision therapy"for MB patients.In this paper,we reviewed the recent studies in medulloblastoma based on cfDNA Liquid Biopsy of CSF.

Simulation of drop breakage in liquid–liquid system by coupling of CFD and PBM: Comparison of breakage kernels and effects of agitator configurations

This work focuses on drop breakage for liquid-liquid system with an adoption of numerical simulation by using computational fluid dynamics and population balance model (PBM) coupled with two-fluid model (TFM). Two different breakage kernels based on identical breakage mechanism but different descriptions of breaking time are take n into account in this work. Eight cases corresp on ding to distinct configurations of agitator are carried out to validate numerical predictions, namely agitators with different porosity and hole diameters, respectively implemented in Cases 1 to 5 and Cases 6 to 8. The results are compared with experimental data for testing the applicability of both kernels. Simulations are implemented, in this work, with an approach of class method for the solution of population balance model by the special-purpose computational fluid dynamics solver Fluent 16.1 based on finite volume method, and the grids used for meshing the solution domain are accomplished in a commercial software Gambit 2.4.6. The effects of configurations of agitator corresponding to different parameters mentioned above on final Sauter mean diameter are equally concentrated in this work. Analysis of both kernels and comparisons with experimental results reveal that, the second kernel has more decent agreement with experiments, and the results of investigations on effects of agitator configurations show that the in fluences of these parameters on Sauter mean diameter are marginal, but appropriate porosity and hole diameter are actually able to decrease Sauter mean diameter. These outcomes allow us to draw general conclusions and help investigate performances of liquid-liquid system.

ANALYSIS OF FLUID FIELD OF LIQUID METAL IN ELECTROMAGNETIC CENTRIFUGAL CASTING

Navier-Stokes equation and Lorentz force equation are used to calculate the fluid field of liquid metal of electromagnetic centrifugal casting (EMCC) in this paper. A field equation is given, which shows the azimuthal velocity closely relates to electrical conductivity, magnetic density, viscosity of liquid metal and radius of casting. The results show that the stationary magnetic field can effectively restrain the fluid flow and the relative velocity between liquid metal and casting mould and the velocity gradient at solid / liquid interface increases with rising magnetic density, which has a great effect on the solidification of liquid metal and crystal growth characteristics.

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC ANALYSIS OF KR-008 IN BIOLOGICAL FLUIDS

A high-performance liquid chromatographic method for the simultaneous determination of KR-008 and its metabolite in biological fluids was developed The samples were injected directly without further treatment,the compounds were separated and analysed on a reversed- phase column under isocratic conditions,including ion pairing.Concentrations in urine and bile were determined by an external standard method.The detection limit was 0.8μg/ml in urine.Preliminary data showed that,following i.p.administration(120mg/kg)of KR-008 to rats,approximately 2.8% of the dose was excreted in urine as unchanged compound and more than 8.9% was as a metabolite;in bile it was 0.73% excreted as unchanged form and above 0.29% as the metabolite.The peak biliary concentration of KR-008 was 0.39mg/ml at 20min after dosing.

Magneto and Electro-Optic Intensity Modulator Based on Liquid Crystal and Magnetic Fluid Filled Photonic Crystal Fiber

We propose a novel light intensity modulator based on magnetic fluid and liquid crystal（LC） filled photonic crystal fibers（PCFs）. The influences of electric and magnetic fields on the transmission intensity are theoretically and experimentally analyzed and investigated. Both the electric and magnetic fields can manipulate the molecular arrangement of LC to array a certain angle without changing the refractive index of the LC. Therefore, light loss in the PCF varies with the electric and magnetic fields whereas the peak wavelengths remain constant. The experimental results show that the transmission intensity decreases with the increase of the electric and magnetic fields. The cut-off electric field is 0.899 V/um at 20 Hz and the cut-off magnetic field is 195 m T. This simple and compacted optical modulator will have a great prospect in sensing applications.

Computational fluid dynamic simulations on liquid film behaviors at flooding in an inclined pipe

The complex liquid film behaviors at flooding in an inclined pipe were investigated with computational fluid dynamic(CFD) approaches. The liquid film behaviors included the dynamic wave characteristics before flooding and the transition of flow pattern when flooding happened. The influences of the surface tension and liquid viscosity were specially analyzed. Comparisons of the calculated velocity at the onset of flooding with the available experimental results showed a good agreement. The calculations verify that the fluctuation frequency and the liquid film thickness are almost unaffected by the superficial gas velocity until the flooding is triggered due to the Kelvin–Helmholtz instability. When flooding triggered at the superficial liquid velocity larger than0.15 m·s-1, the interfacial wave developed to slug flow, while it developed to entrainment flow when it was smaller than 0.08 m·s-1. The interfacial waves were more easily torn into tiny droplets with smaller surface tension, eventually evolving into the mist flow. When the liquid viscosity increases, the liquid film has a thicker holdup with more intensive fluctuations, and more likely developed to the slug flow.

高空机载灭火剂流动输运数值仿真

为探究高空环境对飞机货舱灭火系统内灭火剂流动输运动态的影响,采用Fluent软件对一小型“哈龙”1301机载灭火系统装置管网中灭火剂的流动输运进行数值建模与仿真模拟,计算得到10000 m及13000 m高空下“哈龙”1301灭火剂在管网内的输运和释放动态,并与海平面高度下灭火剂输运释放过程中压力、相体积分数及相变传质速率三个特征变量进行对比分析。结果表明,高空环境下灭火剂的输运释放遵循“三阶段”,但高海拔环境不利于灭火剂的流动输运。该研究结果可为优化机载灭火系统在高空环境下的流动输运能力提供理论依据。

Static Threshold Pressure Gradient Characteristics of Liquid Influenced by Boundary Wettability

We propose an experimental setup to measure the threshold pressure gradient （TPG） of microchannels with different wettability surfaces by the static method in microchannels with diameters from 20 μm to 320 μm, and compare the TPG of microchannels with adsorption of cetyl trimethyl ammonium bromide （CTAB） with that without CTAB adsorption. The results show the existence of TPG in microchannels. The TPG of microchannels increases with decreasing hydrodynamic diameter, and the relation between TPG and diameter is in agreement with the single-log normalization. The TPG of a microchannel with CTAB adsorption decreases obviously as compared with the microchannel without CTAB adsorption. The TPG of microchannels with different wettabilities of boundary surface are different, and the resistance of liquid flow can be reduced by changing the wettability of boundary surfaces.

Thin Film Flow of a Second Grade Fluid over a Stretching/Shrinking Sheet with Variable Temperature-Dependent Viscosity

Effects of variable viscosity on the flow and heat transfer in a thin film on a horizontal porous stretching sheet are analyzed. The steady boundary layer equations for momentum and thermal energy are simplified by using similarity transformations. The resulted and coupled nonlinear differential equations are solved by Homotopy analysis method. The results are presented graphically to interpret various physical parameters appearing in the problem.

Effect of Carrier Liquid on Electrorheological Performance and Stability of Oxalate Group-modified TiO2 Suspensions

By using oxalate group-modified TiO2 nanoparticles as the dispersing phase, different kinds of silicone oil with various viscosities and terminal groups（hydroxyl, hydrogen, and methyl） were used as the dispersing media to prepare different electrorheological（ER） fluids. Their zero-field viscosity, yield stress under direct current electric fields, ER efficiency, shear stability, leakage current density, and sedimentation stability were tested to study the effect of carrier liquid on the properties of ER fluids. The results indicate that the zerofield viscosity, the yield stress, and the leakage current density increase with increasing viscosity of the silicone oils. The effects of the viscosity on the ER efficiency, the shear stability, and the sedimentation ratio depend on the competition between the viscous resistance and the aggregation of the particles. Among the three ER fluids prepared with silicone oil with different terminal groups, hydroxyl-terminated oil based sample has the highest zero-field viscosity, the highest field-induced yield stress and ER efficiency, the largest current density, and the best sedimentation stability.

An unsymmetric constitutive equation for anisotropic viscoelastic fluid

A continuum constitutive theory of corotational derivative type is developed for the anisotropic viscoelastic fluid-liquid crystalline （LC） polymers. A concept of anisotropic viscoelastic simple fluid is introduced. The stress tensor instead of the velocity gradient tensor D in the classic Leslie-Ericksen theory is described by the first Rivlin-Ericksen tensor A and a spin tensor W measured with respect to a co-rotational coordinate system. A model LCP-H on this theory is proposed and the characteristic unsymmetric behaviour of the shear stress is predicted for LC polymer liquids. Two shear stresses thereby in shear flow of LC polymer liquids lead to internal vortex flow and rotational flow. The conclusion could be of theoretical meaning for the modern liquid crystalline display technology. By using the equation, extrusion-extensional flows of the fluid are studied for fiber spinning of LC polymer melts, the elongational viscosity vs. extension rate with variation of shear rate is given in figures. A considerable increase of elongational viscosity and bifurcation behaviour are observed when the orientational motion of the director vector is considered. The contraction of extru- date of LC polymer melts is caused by the high elongational viscosity. For anisotropic viscoelastic fluids, an important advance has been made in the investigation on the constitutive equation on the basis of which a seriesof new anisotropic non-Newtonian fluid problems can be addressed.

Can Heavier Liquid Float on Top of a Lighter One？

We report on a first observation of a floating- spherical Hg （density 13g/cm3） drop on top of a glycerin （density 1.26g/cm3） drop, the latter is hemispherical and about four times larger in volume. This observation is clearly against nature＇s gravity law and has never been reported before. Here we present spectacular high resolution photos that clearly demonstrate this remarkable floating phenomenon. Using milli-Q water, the Hg drop would stay down adhered at the triple line. Instead, the coincidental use of tap water displays the same phenomenon. Increasing the volume of the supporting liquid to a certain value causes the Hg drop to sink. A 5-M NaCl aqueous solution is found enough to show the same floating phenomenon. This floating mercury as a phenomenon is puzzling. On this length scale it seems that surface tension and curvature dominate over gravity.

Experimental research on breakup of 2D power law liquid film

On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination,different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters(injection pressure,ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.

管道冲蚀液-固数值模拟的研究进展

在石油和天然气行业中,管道输送系统的弯管和管汇处极易受到固体颗粒的冲蚀,从而导致管道内承受高压能力削弱,加大了在传输过程的风险。首先对固体颗粒冲蚀机理的发展历程进行了回顾,总结了现阶段固体颗粒冲蚀磨损行为的研究现状,概述了塑性材料和脆性材料冲蚀理论模型。其次,分别从液体流动属性和固体颗粒流动属性两个方面对冲蚀的影响因素进行了阐述,评价了各湍流模型和冲蚀模型的优势和适用范围。随后,综述了中外流体仿真软件在管道冲蚀模拟的研究进展。从弯管到管汇,再到高压泵和旋流分离器等,模拟对象有着复杂的几何形状;网格划分由不变形到可变形,再到无网格划分,大大增加了计算的模拟精度。最后,提出了冲蚀模拟仿真在管道行业的下一步研究和发展方向。为今后的整体管道系统冲蚀预测和位置布局设计提供参考。

基于热-流耦合模型的动力电池液冷系统冷却性能研究

构建了动力电池液冷系统的热-流耦合数值模型,其中冷却液流动过程采用一维非等温管道流方程计算。基于此模型,研究了不同运行参数对液冷系统冷却性能的影响规律。结果表明,当冷却液流量增大时,其功耗增大,但电池均温性提高;当冷却液进口温度升高时,系统泵功增加,但车载制冷系统功耗降低、电池均温性提高;当液冷系统停止温度升高时,其功耗降低,但启停次数呈增加趋势。上述模型对电池液冷系统的设计和优化具有重要意义。

ZCZJ2×3Y-2000型液体钻井液助剂自动加药系统研制

为提高钻井液配置及维护的质量和自动化水平,研制了ZCZJ2×3Y-2000型液体钻井液助剂自动加药系统。该自动加药系统由多仓储液罐、输液计量泵、质量流量计、搅拌器、控制阀及定量配料控制系统等组成,进液计量泵将液体原料桶中的液体钻井液助剂吸入储液罐中暂存。钻井液配制或维护时,定量配料控制系统设定加药参数后,一键式操作可实现出液计量泵将钻井液助剂自动精准输送至泥浆混合系统。该装置的成功应用为钻井液自动精准调控奠定基础,显著提高钻井液配制及维护的自动化和现场HSE水平。

充液直管管系中的固-液耦合振动响应分析

对充液直管管系中固 -液耦合 (包括连接、泊松、摩擦耦合 )对管系轴向振动响应的影响进行了研究。研究结果表明 ,固 -液耦合作用对充液管道系统振动响应影响不容忽视 ;三种固 -液耦合作用中 ,摩擦耦合影响较小 ,连接耦合与泊松耦合影响较大 ,并且其影响机理受到阀门关闭速度的影响 ;当阀门关闭较快时 ,系统响应以水锤响应激励下由连接耦合带来的受迫振动为主 ;当阀门关闭较慢时 ,系统以由连接耦合与泊松耦合带来的管道应力波为主。

江西九瑞地区岩浆岩系统与成矿

九瑞地区曾经历过长期多旋回构造运动,其中燕山旋回所伴随的岩浆活动是本区内生铜金矿床形成的关键条件之一.本区燕山期岩浆岩以同熔型中酸性侵入岩为主,多期次侵位的众多岩体构成一岩浆岩系统,该系统在空间上具有垂向多层分支和横向分带结构,不同深度层次岩浆岩的形态、产状、规模和成矿作用是不同的.本文通过计算武山岩株体岩浆热能和蚀变矿化所需热能,证明中—浅部岩浆体冷凝所释放的热量,远不能满足武山这类大型铜矿形成所需能量,只能由深部岩浆房的超临界气液流体通过对流带来,古地下水对流系统也参与了热能的分配和成矿.

基于ANSYS Workbench的输液管道系统振动控制仿真研究

以折弯式管道为例研究了输液管道系统的振动控制。首先,建立了输液管道系统的运动方程,但由于方程在离散过程中结构矩阵和流体矩阵的数值计算量过大,在计算过程中常出现溢出错误,因此使用模态缩减法简化矩阵以便于进行计算;其次,在高频振荡流体载荷的作用下,利用ANSYS Workbench的双向隐式迭代法计算管道系统的动力学特性;最后,建立带有节流孔板的管道系统有限元模型,研究了节流孔板对系统振动的抑制作用。计算结果表明节流孔板对输液管道系统的振动控制是非常有效的。

深水FLAT-PRO合成基钻井液体系研究及应用

为了解决深水钻井过程中安全密度窗口窄的技术难题,以低黏度气制油作为基液,对合成基钻井液乳化剂、润湿剂及流型调节剂等关键处理剂进行了研制和优化,构建了深水FLAT-PRO合成基钻井液体系。室内性能评价结果表明,新构建的FLAT-PRO合成基钻井液体系具有流变性好、动切力与Φ6受温度及压力影响小、抗污染能力强、沉降稳定性好等特点。目前新构建的深水FLAT-PRO合成基钻井液体系已在我国南海西部超深水井中取得成功应用,具有较好的推广应用价值。