Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

Identification prognostic features related to sphingolipid metabolism and experimental validation of TRIM47 in hepatocellular carcinoma

Background:The specific impact of sphingolipid metabolism on developing hepatocellular Carcinoma(HCC)remains unclear.This study aims to explore the relationship between sphingolipid metabolism and HCC prognosis,immune response,and drug sensitivity.Methods:Data were obtained from The Cancer Genome Atlas(TCGA)-Hepatocellular Carcinoma(LIHC)and Gene Expression Omnibus(GEO,GSE14520 datasets).47 sphingolipid metabolism genes were obtained from the Kyoto Encyclopedia of Genes and Genomes(KEGG)database.After classifying HCC samples using the Non-negative Matrix Factorization(NMF)clustering method,differentially expressed genes were screened.Then,8 risk genes were obtained by univariate analysis,survival random forest reduction and lasso analysis.The expression of 8 risk genes was verified in vitro.Results:8 risk genes were used to construct the Sphingolipid score model.High-Sphingolipid score predicted poor prognosis of HCC patients.Sphingolipid score was associated with immune checkpoints(IL-1B,TLR4,TGFB1,and IL-10),immune cells(Th2,Treg,MDSC,Neutrophil,Fibroblasts and macrophage),and MAPK Cascade.In the High-Sphingolipid score group,a significantly higher proportion of patients with TP53(p53)mutations was significantly higher(56%).Furthermore,patients with a high-Sphingolipid score were predicted to have a higher sensitivity to chemotherapy drugs.In vitro validation showed that compared with normal liver cells LX-2,TRIM47,and S100A9 significantly increased in liver cancer cells Hep G2,MHCC-97H,and Hep3B2.1-7,while SLC1A7,LPCAT1,and CFHR4 significantly decreased.Silencing TRIM47 reduced the proliferation and promoted apoptosis.The levels of ceramide synthesis-related indexes(CERS1,CERS6,CERS5,and SPTLC2)increased,and the ACER3 related to catalytic hydrolysis decreased.Conclusion:We constructed a sphingolipid metabolism-related prognostic signature(Sphingolipid score)based on 8 risk genes.TRIM47 may affect the development of liver cancer by regulating the relevant indicators of ceramide synthesis and catalytic hydrolysis.

数字胸腔引流系统在肺切除术中的应用价值

肺切除术后,胸腔引流管理是决定患者术后病程的关键,延迟拔管影响恢复速度和住院时间。传统胸腔闭式引流瓶已被广泛应用于相应患者,但存在一定局限性,尤其是肺切除术后存在肺漏气时,通常面临着长期不能拔除胸腔闭式引流管的风险。数字胸腔引流系统因其独特的优势可加快肺部漏气的愈合、减少胸腔引流量,进而缩短住院时间,其效果在多项研究中都得到了验证,本文就数字胸腔引流系统在肺切除术中的应用价值进行综述,并就其进一步有效应用进行讨论。

Three-dimensional double-rough-walled modeling of fluid flow through self-affine shear fractures

This study proposes a double-rough-walled fracture model to represent the natural geometries of rough fractures.The rough surface is generated using a modified successive random additions(SRA)algorithm and the aperture distribution during shearing is calculated using a mechanistic model.The shear-flow simulations are performed by directly solving the Navier-Stokes(NS)equations.The results show that the double-rough-walled fracture model can improve the accuracy of fluid flow simulations by approximately 14.99%-19.77%,compared with the commonly used single-rough-walled fracture model.The ratio of flow rate to hydraulic gradient increases by one order of magnitude for fluids in a linear flow regime with increment of shear displacement from 2.2 mm to 2.6 mm.By solving the NS equations,the inertial effect is taken into account and the significant eddies are simulated and numerically visualized,which are not easy to be captured in conventional experiments.The anisotropy of fluid flow in the linear regime during shearing is robustly enhanced as the shearing advances;however,it is either increased or decreased for fluids in the nonlinear flow regime,depending on the geometry of shear-induced void spaces between the two rough walls of the fracture.The present study provides a method to represent the real geometry of fractures during shearing and to simulate fluid flow by directly solving the NS equations,which can be potentially utilized in many applications such as heat and mass transfer,contaminant transport,and coupled hydro-thermo-mechanical processes within rock fractures/fracture networks.

The structure,tensile properties and water resistance of hydrolyzed feather keratin-based bioplastics

Feather,as a by-product of the poultry industry,has long been treated as a solid waste,which causes environmental and economic problems.In this work,the hydrolyzed feather keratin(HFK)was extracted from the chicken feather using a cost-effective method of alkali-extraction and acid-precipitation by applying urea and sodium sulfide.The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process.The thermal analysis showed that high temperature and high pressure improved the compatibility between the glycerol and the HFK molecules.Also it was shown that the addition of water is necessary in the hot-pressing process of films.The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol.By increasing the glycerol content,the film tensile strength(σ_b)decreases from 10.5 MPa to 5.7 MPa and the solubility increases from 15.3% to 20.9%,while the elongation at break(εb)achieves the maximum value of 63.8% for the film with 35% glycerol.The swelling was just below 16.9%at 25 °C for 24 h,suggesting a good stability of the films in water.The water vapor permeability(WVP)varied between 3.02 × 10^(-10)g · m^(-2)· s^(-1)· Pa^(-1)and 4.11 × 10^(-10)g · m^(-2)· s^(-1)· Pa^(-1)for the films with 20% and40% glycerol,respectively.The HFK film was uniform,translucent and tough,which could be used in packaging and agricultural field.

Solute Removal Analysis of a Large-Scale Fracture Plane Considering Different Flow Paths and Different Hydraulic Head Differences

An experimental and numerical study was carried out to investigate the solute removal process through a large-scale fracture plane considering different flow paths and hydraulic head differences.The visualization techniques were utilized in the experiment to capture the removal process images,which were then transferred to binary images.The variations in dimensionless concentration,which is defined as saturation of solute phase,were analyzed.With increasing hydraulic head difference,the speed of solute removal increases and the dimensionless concentration decreases.The flow paths result in different solute distribution patterns and different mechanisms for solute removal such as advection and diffusion,thus the curves of dimensionless concentration versus time are different.The dimensionless concentration over time decreases from approximately 1,which is smaller than 1 due to the existence of bubbles,to approximately 0,which is larger than 0 because the folds of the background are dealt as“solute”.A significant longer time is needed to achieve a certain fixed dimensionless concentration for a smaller hydraulic head difference.With the finite element software COMSOL multiphysics,the solute removal process,flow velocity fields,flow streamlines,as well as the hydraulic pressure fields were analyzed,which shows a good consistency with the experimental results.In practical engineering,when the solute pollutes the underground environment,the removal ability can be more significantly enforced by immediately applying a larger hydraulic head difference along a longer distance between the inlet and outlet boundaries.

Nanofibrillation of a Bleached Acacia Pulp by Grinding with Carboxymethylation Pretreatment

In this study,carboxymethylation,which introduces carboxyl groups to hydroxyl sites in pulp fibers,was used as a pretreatment before mechanical nanofibrillation.The carboxyl group content of the pulp fibers was greatly affected by the dosage of chloroacetic acid and the reaction temperature.During the following fibrillation process,it was found that pulp fibers with higher carboxyl group content exhibited higher water holding capacities and smaller dimensions.A more homogenous structure with a higher amount of individual fibrils was also observed in FE-SEM images of pulp fibers with high carboxyl group content.This can be explained by a high ionic group content in the fiber wall resulting in lower delamination resistance,making the fibrils easier to separate.Carboxymethylation pretreatment as a facilitator of fibrillation in cellulosic pulps is an efficient way to obtain cellulose nanofibrils and consequently decrease the energy consumption of the process.

The Totally Non-positive Matrix Completion Problem

In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has. in general, a negative answer. Therefore, our question is for what kind of labeled graphs G each partial totally non-positive matrix whose associated graph is G has a totally non-positive completion? If G is not a monotonically labeled graph or monotonically labeled cycle, we give necessary and sufficient conditions that guarantee the existence of the desired completion.

The Nonlinear Coupling of Oscillating Bubble and Floating Body with Circular Hole

The fluid-structure interaction of the oscillating bubble and floating body with circular hole is essentially the nonlinear coupling problem among the incomplete movable boundary,free surface and bubble.This problem is particularly complicated in bubble dynamics.Combined with the volume of fluid method,the Eulerian finite element method is employed to deal with the fluid movement.Based on the improved penalty immersed boundary method,the transient axisymmetric numerical model is established in this paper,considering the fluid-structure interaction effect.The results of simulation are consistent with those of the electric discharge bubble experiment and explosion experiment.Subsequently,considering the influence of the hole size,floating body density,explosive location,and buoyancy,this complex fluid-structure interaction problem is analyzed systematically.Through numerical simulation,we get some new conclusions.When the radius of the hole Rh less than the maximum radius of the oscillating bubble,the changes in the whole system are incredibly intense,and the free surface crushing will emerge.The energy of the bubble acts more on the radial direction of the floating body,when the explosive location parameter is small.When the floating body has the same density as the water,the multiple spike skirt is displayed vividly.And the buoyancy of fluid can produce a lifting effect on the floating body.

基于真实世界数据的食管鳞癌在新辅助治疗联合PD-1/PD-L1抑制剂的安全性及疗效分析

目的:免疫检查点抑制剂联合化疗在食管癌的治疗中具有较好的疗效,然而免疫治疗在局部晚期食管癌围手术期的应用尚缺乏共识。本研究通过分析真实世界的数据,为免疫检查点抑制剂在食管癌新辅助治疗中的临床应用提供借鉴和依据。方法:本研究分析2020年3月至2021年8月就诊于河北医科大学第四医院,经病理证实为食管鳞癌的局部晚期患者,经评估建议行新辅助治疗联合免疫检查点抑制剂,后接受规范的食管癌根治手术,共纳入患者152例。观察终点为病理完全缓解(pathologic complete response,pCR)率,主要病理缓解(major pathologic response,MPR)率,显微镜下无残留(R0)切除率、术后并发症、肿瘤退缩分级、无病生存(disease-free survival,DFS)率,并探索最优的新辅助化免联合治疗的周期数。结果:R0切除94.1%(143/152),术后病理评估发现按照美国病理学家协会(CAP)肿瘤退缩分级标准,0级、1级、2级、3级的比例分别为29.6%、11.2%、25.7%、33.5%;pCR率25%。16.4%出现新辅助治疗相关不良反应;术后降期率62.5%。术后并发症:90天术后死亡率为0,发生术后并发症25%,吻合口瘘的发生率7.8%,肺炎发生率9.2%。术前免疫周期数为2~3次的患者,术后病理类型为CAP分级0~2级的占比92.1%,而其他周期数的患者术后病理类型为CAP分级0~2级的占比7.9%(P=0.007)。全组患者中位随访时间16.4(15.0~7.8)个月,1年DFS率96.7%,2年DFS率87.5%。结论:程序性细胞死亡因子-1/配体-1(programmed death-1/programmed cell death-ligand 1,PD-1/PD-L1)抑制剂在局部晚期食管鳞癌患者的新辅助治疗中安全可行,R0切除率满意,pCR率满意,新辅助化疗联合免疫检查点抑制剂治疗明显达到降期的目的。多数患者术后治疗受限,建议辅助治疗尽可能放到术前。术前2~3个周期患者可能有更高的病理缓解率。

HPLC⁃DAD法同时测定当归祛风合剂中6种成分

目的建立HPLC-DAD法同时测定当归祛风合剂中阿魏酸、毛蕊花糖苷、芍药苷、白鲜碱、升麻素苷、甘草苷的含量。方法该药物50%甲醇提取液的分析采用Ultimate C_(18)色谱柱(250 mm×4.6 mm,5μm);流动相0.1%磷酸-乙腈,梯度洗脱;体积流量1.0 mL/min;柱温35℃;检测波长230、236、240、280、334 nm。结果6种成分在各自范围内线性关系良好(r>0.9994),平均加样回收率95.56%~105.29%,RSD 2.77%~3.92%。结论该方法准确可靠,可为当归祛风合剂质量控制、临床应用提供参考。

Antioxidant and anti-HepG2 cell activities of a novel bioactive peptide from cowhide collagen in vitro

In the present study,the antioxidant and anti-human liver cancer(HepG2)cells effects of bioactive peptides from cowhide collagen(BPCC)were evaluated.BPCC exhibited significant scavenging effect on l,1-diphenyl-2-picrylhydrazyl(DPPH)radicals((60.09±3.51)%),2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)radicals((77.40±3.10)%)and hydroxyl radicals((56.00±2.30)%)as well as strong reducing power(0.320士0.025).Meanwhile,BPCC effectively protected biomacromolecules including proteins,lipids and DNA from oxidative damage induced by Cu^(2+)H_(2)O_(2)and 2,2'-azobis(2-methylpropionamidine)dihydrochloride(AAPH).Moreover,BPCC significantly inhibited cell viability of HepG2 cells in a dose-dependent manner with an estimated IC_(50)of 7.61 mg/mL.The results of 4',6-diamidino-2-phenylindole(DAPI)and acridine:orange/ethidium bromide(AO/EB)staining demonstrated the apoptotic morphological changes and cell mediated death in BPCC treated HepG2 cells.In addition,BPCC induced decrease of mitochondrial membrane potential(MMP)in HepG2 cells.Therefore,the present finding proved that BPCC encompasses significant antioxidant activity and anticancer property on HepG2 cells and can be used as alternative food antioxidants for cancer prevention benefits.

细火针治疗神经性皮炎临床观察

目的观察细火针治疗神经性皮炎的临床疗效。方法将60例神经性皮炎患者随机分为治疗组和对照组,每组30例。治疗组给予细火针治疗,每周治疗1~2次,连续治疗2周,为1个疗程,同时口服氯雷他定口腔崩解片,每日1片;对照组给予地奈德外用,第1周每日1次,第2周隔日1次,连续使用2周,同时口服氯雷他定口腔崩解片,每日1片。结果治疗组痊愈12例、显效10例、有效6例、无效2例,总有效率为93.3%(28/30);半年内,痊愈的12例中,出现复发3例,复发率为10.0%(3/30);对照组痊愈16例,显效6例,有效7例,无效1例,总有效率为96.7%(29/30)。半年内,复发者9例,复发率为30.0%(9/30)。结论细火针治疗神经性皮炎,疗效较好,减低了激素依赖性,复发率较低,值得推广。

Dynamic impact experiment and response characteristics analysis for 1:2 reduced-scale model of hydraulic support

It is significant to research the impact resistance properties of hydraulic support due to its key support role in the fully mechanized mining face.However,it is difficult for the entire hydraulic support to implement the impact experiment underground and analyze the response characteristic.Therefore,a dynamic impact experiment for the entire hydraulic support was proposed in this paper,where a 1:2 reducedscale model of hydraulic support was designed and its response characteristics under dynamic impact load were analyzed.Firstly,a comprehensive monitoring scheme was proposed to achieve an effective monitoring for dynamic response of hydraulic support.Secondly,a multi-scale impact experiment was carried out for the entire hydraulic support and dynamic behaviors of hydraulic support under the multi-scale impact load were revealed by experimental data.Then a dynamic impact experiment of the entire hydraulic support was simulated in ADAMS with the same experiment conditions,and the experimental and simulation data were verified mutually.Finally,the characteristics of energy conversion and dissipation of the entire experiment system after impact were analyzed.The experiment results showed that the impact resistance properties of hydraulic support largely depended on the initial support conditions and different vertical rigidities affected energy distribution proportion of the entire support system.

Guaranteed Cost Consensus for High-dimensional Multi-agent Systems With Time-varying Delays

Guaranteed cost consensus analysis and design problems for high-dimensional multi-agent systems with time varying delays are investigated. The idea of guaranteed cost con trol is introduced into consensus problems for high-dimensiona multi-agent systems with time-varying delays, where a cos function is defined based on state errors among neighboring agents and control inputs of all the agents. By the state space decomposition approach and the linear matrix inequality(LMI)sufficient conditions for guaranteed cost consensus and consensu alization are given. Moreover, a guaranteed cost upper bound o the cost function is determined. It should be mentioned that these LMI criteria are dependent on the change rate of time delays and the maximum time delay, the guaranteed cost upper bound is only dependent on the maximum time delay but independen of the Laplacian matrix. Finally, numerical simulations are given to demonstrate theoretical results.

Prolonged simulation of near-free surface underwater explosion based on Eulerian finite element method

n the area of naval architecture and ocean engineering,the research about the underwater xplosion problem is of great significance.To achieve prolonged simulation of near-free surface underwater explosion,the underwater explosion transient numerical model is established in this paper based on compressible Eulerian finite element method(EFEM).Compared with Geers Hunter formula,EFEM is availably validated by simulating the free-field underwater xplosion case.Then,the bubble pulsation and flow field dynamic characteristics of the cases with different underwater explosive depth are compared in this work.Lastly,the height of the water hump and the pressure of flow flied are analyzed quantitatively through the simulation results.

ia-PNCC: Noise Processing Method for Underwater Target Recognition Convolutional Neural Network

Underwater target recognition is a key technology for underwater acoustic countermeasure.How to classify and recognize underwater targets according to the noise information of underwater targets has been a hot topic in the field of underwater acoustic signals.In this paper,the deep learning model is applied to underwater target recognition.Improved anti-noise Power-Normalized Cepstral Coefficients(ia-PNCC)is proposed,based on PNCC applied to underwater noises.Multitaper and normalized Gammatone filter banks are applied to improve the anti-noise capacity.The method is combined with a convolutional neural network in order to recognize the underwater target.Experiment results show that the acoustic feature presented by ia-PNCC has lower noise and are wellsuited to underwater target recognition using a convolutional neural network.Compared with the combination of convolutional neural network with single acoustic feature,such as MFCC(Mel-scale Frequency Cepstral Coefficients)or LPCC(Linear Prediction Cepstral Coefficients),the combination of the ia-PNCC with a convolutional neural network offers better accuracy for underwater target recognition.

MINDTL： Multiple Incomplete Domains Transfer Learning for Information Recommendation

Collaborative filtering is the most popular and successful information recommendation technique. However, it can suffer from data sparsity issue in cases where the systems do not have sufficient domain information. Transfer learning, which enables information to be transferred from source domains to target domain, presents an unprecedented opportunity to alleviate this issue. A few recent works focus on transferring user-item rating information from a dense domain to a sparse target domain, while almost all methods need that each rating matrix in source domain to be extracted should be complete. To address this issue, in this paper we propose a novel multiple incomplete domains transfer learning model for cross-domain collaborative filtering. The transfer learning process consists of two steps. First, the user-item ratings information in incomplete source domains are compressed into multiple informative compact cluster-level matrixes, which are referred as codebooks. Second, we reconstruct the target matrix based on the codebooks. Specifically, for the purpose of maximizing the knowledge transfer, we design a new algorithm to learn the rating knowledge efficiently from multiple incomplete domains. Extensive experiments on real datasets demonstrate that our proposed approach significantly outperforms existing methods.

Transport properties of Tl_(2)Ba_(2)CaCu_(2)O_(8) microbridges on a low-angle step substrate

Tl-based superconducting devices have been drawn much attention for their high transition temperature(T_c), which allow the high temperature superconductors(HTS) devices to operate at temperature near 100 K. The realization of Tlbased devices will promote the research and application of HTS devices. In this work, we present transport properties of Tl_(2) Ba_(2) CaCu_(2) O_(8)(Tl-2212) microbridges across a low-angle step on LaAlO_(3)(LAO) substrate. We experimentally demonstrate intrinsic Josephson effects(IJEs) in Tl-2212 films by tailoring the geometry, i.e., reducing the width of the microbridges. In the case of a 1 μm width microbridge, in addition to the observation of voltage branches and remarkable hysteresis on the current–voltage(I–V) characteristics, the temperature dependence of differential resistance shows a finite resistance above 60 K when the bias current is below the critical current. For comparison, the wider microbridges are also investigated, exhibiting a highly critical current but do not showing obvious IJEs.

Application of Cellulose Nanofibril as a Wet-end Additive in Papermaking:A Brief Review

Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceutical applications,as well as in industrial applications such as paints,drill muds,packaging,and papermaking.The application of CNF in papermaking is expected to be implemented in the near future to broaden the commercial market of cellulose.Numerous studies and patents have reported on the manufacturing,properties,and applications of nanocellulose.This present paper focuses on the recent progresses in the application of CNF as a wet-end additive in papermaking.