CT Texture Analysis: A Potential Biomarker for Evaluating KRAS Mutational Status in Colorectal Cancer

Objective Texture analysis is deemed to reflect intratumor heterogeneity invisible to the naked eyes.The aim of this study was to evaluate the feasibility of assessing the KRAS mutational status in colorectal cancer(CRC)patients using CT texture analysis.Methods This retrospective study included 92 patients who had histopathologically confirmed CRC and underwent preoperative contrast-enhanced CT examinations.The patients were assigned into a training cohort(n=51)and a validation cohort(n=41).We placed the region of interest in the tumour regions on the selected axial images using software of lexRad to extract a series of quantitative parameters based on the spatial scaling factors(SSFs),including mean,standard deviation(SD),entropy,mean of positive pixels(MPP),skewness,and kurtosis.The texture parameters and clinical characteristics(age,gender,tumour location,histopathology;tumour size,1 N,M stages)were compared between the mutated and wild-type KRAS patient groups in training cohort and validation cohort.Before building the multiple feature classifier,we calculated the correlations of the features using Pearsons correlation coefficient,and if any two features were significantly correlated,the one with lower AUC was removed.Ultimately,only the most discriminative isolated features were combined to train a supporting vector machine(SVM)classifier.The receiver operating characteristic(ROC)curve was processed for evaluating the diagnostic efficiency of texture parameters in differentiating CRC patients with mutated KRAS from those with wild-type KRAS.Results None of the clinical characteristics were significant different between CRC patients with wild-type KRAS and mutated KRAS in both cohorts.For predicting the expression of mutated KRAS in CRC patients,the perfect model which combined skewness on SSF 5 by unenhanced CT,entropy on SSF 2,skewness and kurtosis on SSF 0,and kurtosis and mean on SSF 3 by enhanced CT,showed a desirable AUC of 0.951(95%CI:0.895-1,P<0.001),with a sensitivity of 88.9%and a specificity of 91.7%,when the cut-off value was 0.46 in the training cohort;while in the validation cohort,the AUC value was 0.995(95%CI:0.982-1,P<0.001),the sensitivity was 100%,and the specificity was 93.7%when the cut-off value was 0.28.Conclusion It is feasible to evaluate the KRAS mutational status in CRC using CT texture analysis.

A New X-band Weather Radar System with Distributed Phased-Array Front-ends: Development and Preliminary Observation Results

A novel weather radar system with distributed phased-array front-ends was developed. The specifications and preliminary data synthesis of this system are presented, which comprises one back-end and three or more front-ends. Each front-end, which utilizes a phased-array digital beamforming technology, sequentially transmits four 22.5°-width beams to cover the 0°–90° elevational scan within about 0.05 s. The azimuthal detection is completed by one mechanical scan of0°–360° azimuths within about 12 s volume-scan update time. In the case of three front-ends, they are deployed according to an acute triangle to form a fine detection area(FDA). Because of the triangular deployment of multiple phased-array front-ends and a unique synchronized azimuthal scanning(SAS) rule, this new radar system is named Array Weather Radar(AWR). The back-end controls the front-ends to scan strictly in accordance with the SAS rule that assures the data time differences(DTD) among the three front-ends are less than 2 s for the same detection point in the FDA. The SAS can maintain DTD < 2 s for an expanded seven-front-end AWR. With the smallest DTD, gridded wind fields are derived from AWR data, by sampling of the interpolated grid, onto a rectangular grid of 100 m ×100 m ×100 m at a 12 s temporal resolution in the FDA. The first X-band single-polarized three-front-end AWR was deployed in field experiments in 2018 at Huanghua International Airport, China. Having completed the data synthesis and processing, the preliminary observation results of the first AWR are described herein.

Research on Lubrication Model of Rock Bit Bearings with Non-Newtonian Medium

Lubrication media of rock bit journal bearing is non-Newtonian fluid, and because of structure limitations, lubricant supply is only from the inside track and its rheological properties are relatively complex. In general studies, the non- Newtonianism of lubrication media of rock bit journal bearing is neglected to simplify the research process. Based on the universal Reynolds equation of non-Newton media, the mathematical model of lubrication analysis was suitable for the rock bit bearing working conditions was established. Then according to the experimental results of rheological properties of RB-type lubricating grease, the equivalent viscosity of the model was established and this model can be solved by the method used in solving the Reynolds equation of Newton fluid.

Tribological properties of oil-impregnated polyimide in double-contact friction under micro-oil lubrication conditions

Oil-impregnated porous polyimide(iPPI)materials are usually used as retainer for bearings.In these bearings,balls and rings,balls and retainers are two different kinds of contact.In this paper,the friction and wear properties of iPPI were investigated using steel(disc)–steel(ball)–iPPI(pin)double-contact friction test rig for simulating the actual contact in bearings.The results show that compared with that of iPPI–steel single contact,the friction coefficient of iPPI–steel in double contacts is lower and decreases with the amount of additional oil.The surface of iPPI in single contact suffers more wear compared with that in double contacts.Different from single contact,the worn surfaces of iPPI in double contacts are blackened.The Raman spectra of worn surfaces of balls and discs indicate thatα-Fe_(2)O_(3) and Fe_(3)O_(4) were formed during rubbing of the double contacts.Many nanoscale iron oxide particles are found on the worn surfaces of iPPI in double contacts;on the contrary,few particles could be found on the surface in single contact.In double-contact friction,the nanoscale wear debris penetrates inside the iPPI material through the process of extruding and recycling of oil,which is the mechanism of the blackening of the iPPI worn surfaces.The studies show that the double-contact friction method is a new and effective method to study the friction in bearings,especially for those with polymer retainer.

溢流管结构对天然气水合物用旋流器分离性能的影响

建立了主直径100 mm的旋流器模型,采用计算流体力学(CFD)方法研究了溢流管内径、插入深度及壁厚对旋流器分离天然气水合物性能的影响规律。结果表明,入口流速为9m/s时,随溢流管内径增大,水合物分离效率增大,砂的分离效率降低,旋流器的压力降逐渐减小;随溢流管壁厚增大,水合物和砂的分离效率稍有增大,旋流器的压力降先增大后减小;随溢流管插入深度增大,水合物分离效率先减小后增大,砂的分离效率先增大后减小,旋流器的压力降波动较小。溢流管内径对旋流器分离天然气水合物性能的影响最大,插入深度次之,壁厚的影响最小。

旋流分离对天然气水合物除砂提纯的影响

针对固态流化开采方法开采海底天然气水合物含砂量大导致开采效率低的问题,提出原位分离工艺,设计了旋流分离装置,基于该装置利用CFD数值模拟方法研究了固相(砂和水合物颗粒)直径、入口浆体流量及浆体中砂浓度对装置分离性能的影响。结果表明,在研究范围内,砂和水合物分离效率大部分高于60%,最高达98.72%,压降大部分低于0.5 MPa,最低至0.03MPa。砂粒分离效率随固相粒径增大先增大后趋于平稳,随浆体入口流量增大先增大后减小,随砂浓度增大而降低;水合物分离效率随固相粒径增大先增大后趋于平稳,随浆体入口流量增大先增大后减小,随砂浓度增大而降低。溢流口和底流口压降几乎不随固相粒径变化,随砂浓度和浆体入口流量增大而增大。固相粒径、入口流量、砂浓度对分离性能有较大影响,在砂粒径大于20?m、水合物粒径大于40?m、浆体入口流量约5 m3/h、入口砂浓度不超过25vol%的条件下分离性能良好。

天然气水合物提纯螺旋分离器性能数值模拟

针对海底浅层天然气水合物开采中产砂量大而造成管路堵塞、设备磨损的问题,基于固态流化开采方法,提出天然气水合物原位分离的思路,结合水合物混合浆体物性参数设计井下原位螺旋分离器,采用CFD-Fluent商业软件建立分析模型并进行模型正确性验证,考察了固相水合物体积浓度、固相砂体积浓度和入口流速对分离装置性能的影响。结果表明,研究范围内砂去除率和水合物回收率均约为80%,随水合物体积分数增大,砂去除率和水合物回收率变化非常小,分离器压降变化很小;随砂体积分数增大,砂去除率急剧降低,而水合物回收率急剧增加,压降急剧增大;随入口速度增加,砂去除率和水合物回收率不断增大,分离器压降不断增大。设计的螺旋分离器在水合物原位除砂提纯中性能优异,水合物饱和度对分离器性能影响不大,但粉砂浓度对分离器性能影响较明显,工程应用中需要重点考虑;入口速度对分离器分离性能起关键性作用,决定了分离器的处理能力,适当提高入口速度可一定程度提高分离器的分离效率。

EDA-assisted synthesis of multifunctional snowflake-Cu_(2)S/CdZnS S-scheme heterojunction for improved the photocatalytic hydrogen evolution

The charge separation efficiency is one of the main factors affecting the solar photocatalytic decomposition of water to produce hydrogen.Constructing a unique heterojunction can accelerate the separation and transfer of photo-generated charges,and effectively improve the photocatalytic efficiency,which is considered a potential strategy.Accordingly,the 2%Cu_(2)S/CZS step-scheme(S-scheme)heterojunction based on morphology and electronic structure was successfully prepared via simple hydrothermal method.Compared with the monomer Cu_(2)S and Cd Zn S,the hydrogen evolution rate of 2%Cu_(2)S/CZS samples is significantly increased.In particular,the 2%Cu_(2)S/CZS not only shows high hydrogen evolution rate of 5904μmol g^(-1)h^(-1)(3.19 times than original Cd Zn S),but also presents preferable cyclic endurance.According to the characterization,we believe that the introduction of Cu_(2)S has the following three advantages:(i)The snowflake structure of Cu_(2)S reduces the agglomeration of granular Cd Zn S.(ii)The Cu_(2)S with narrow band gap broadens the light response range of the composite catalyst.(iii)The Cu_(2)S was introduced into Cd Zn S to form S-scheme heterojunction,which accelerated the separation and transfer of photo-generated charge.This work broadens the idea of designing efficient photocatalyst of hydrogen evolution.

Water environment protection and sustainable development in townlet of China: A case study in Taicang

The Environmental Kuznets Curve(EKC) model was applied to investigate the relationship between economic growth and water environment quality based on panel data of Taicang during 2010–2017. The typical inversed-U shaped relationship has been obtained between GDP(gross domestic product) and indicators of ammonia, total nitrogen(TN) and total phosphorus(TP), respectively. The EKC turning point appeared when the GDP per capita was around US$2270, which was much lower than those in some developed countries(US$11,200). However, the decoupling between chemical oxygen demand(COD) and GDP per capita occurred even before this period, which should be attributed to the strict COD emission regulation being implemented since 2010. Further, analysis based on the Tapio decoupling coefficient elasticity model analyzed the ammonia nitrogen and economic development of each industry. We found that the agriculture no-point was strong decoupling in 2011–2014, then came to Recessive decoupling. The domestic wastewater had been in a strong decoupling state;Both urban non-point and industry experienced expansive negative decoupling, due to strict policy that prioritizes the environment over development and the investment in improvement of environment and techniques, both of them gradually came to strong decoupling. The result demonstrated that the EKC turning point could be appear in earlier economic stage and the decoupling coefficient elasticity could be improved through taking strong regulation measures.