Effect of Nitric Oxide on Esophageal Cancer Cell Line TE-1

Objective To investigate the radiosensitizing effect of nitric oxide(NO) combined with radiation on esophageal cancer cell line TE-1.Methods Methyl thiazolyl tetrazolium(MTT) assay was used to assess the effects of NO and radiation on TE-1 cells regarding inhibition of cell proliferation.Flow cytometry was used to examine the effect of NO and radiation on cell apoptosis and cycle.Reverse transcription polymerase chine reaction and Western blot were used to evaluete the effect of NO on mRNA and protein expression of manganese superoxide dismutase(MnSOD).Results NO inhibited the proliferation of TE-1 cells while significantly enhancing their radiosensitivity.The application of NO combined with radiation significantly increased the apoptosis rate and G2/M phase proportion of TE-1 cells,with substantial decreases in the MnSOD mRNA and protein expression levels.Conclusions NO reduces the MnSOD mRNA and protein expression levels by affecting TE-1 cell cycle,further inhibiting the apoptosis of esophageal cancer cells and enhancing the killing effect of radiation on esophageal cancer cells.

Colorectal adenocarcinoma patients with M1a diseases gain more clinical benefits from palliative primary tumor resection than those with M1b diseases: A propensity score matching analysis

BACKGROUND Surgical resection is regarded as the only potentially curative treatment option for patients with metastatic colorectal cancer(CRC).The National Comprehensive Cancer Network clinical practice guidelines do not recommend palliative surgery unless there is a risk of severe symptoms.However,accumulating evidence has shown that palliative surgery is associated with more favorable outcomes for patients with metastatic CRC.AIM To investigate the separate role of palliative primary tumor resection for patients with stage IVA(M1a diseases)and stage IVB(M1b diseases)colorectal adenocarcinoma(CRA).METHODS CRA patients diagnosed from 2010 to 2015 with definite M1a and M1b categories according to the 8th edition of American Joint Committee on Cancer staging system were selected from the Surveillance Epidemiology and End Results(SEER)database.To minimize potential selection bias,the data were adjusted by propensity score matching(PSM).Baseline characteristics,including gender,year of diagnosis,age,marital status,primary site,surgical information,race,grade,chemotherapy,and radiotherapy,were recorded and analyzed.Univariate and multivariate analyses were performed to explore the separate role of palliative surgery for patients with M1a and M1b diseases.RESULTS A total of 19680 patients with metastatic CRA were collected from the SEER database,including 10399 cases of M1a diseases and 9281 cases of M1b diseases.Common independent prognostic factors for both M1a and M1b patients included year of diagnosis,age,race,marital status,primary site,grade,surgery,and chemotherapy.After PSM adjustment,3732 and 3568 matched patients in the M1a and M1b groups were included,respectively.Patients receiving palliative primary tumor resection had longer survival time than those without surgery(P<0.001).For patients with M1a diseases,palliative resection could increase the median survival time by 9 mo;for patients with M1b diseases,palliative resection could prolong the median survival time by 7 mo.For M1a diseases,patients with lung metastasis had more clinical benefit from palliative resection than those with liver metastasis(15 mo for lung metastasis vs 8 mo for liver metastasis,P<0.001).CONCLUSION CRA patients with M1a diseases gain more clinical benefits from palliative primary tumor resection than those with M1b diseases.Those patients with M1a(lung metastasis)have superior long-term outcomes after palliative primary tumor resection.

非肥胖性糖尿病小鼠干眼模型的初步建立

目的:初步建立非肥胖性糖尿病(NOD)小鼠蒸发过强型干眼模型,通过研究小鼠眼表组织病理变化,初步探讨其作为糖尿病性干眼模型的可行性。方法:选取40只雌性NOD小鼠,NOD小鼠自发糖尿病为实验组,同时选取未自发糖尿病的NOD小鼠作为正常对照组。实验组NOD小鼠置于40%以下湿度环境,每天皮下注射0.5mg/0.2mL氢溴酸菪胺,并置于可控干燥箱中,每天通风12h,制作蒸发过强型干眼模型。在造模后的第1、7、10、14d采用酚红棉线实验测量泪液分泌量,PAS染色检查结膜杯状细胞形态和数目;在造模后的第10d,进行角膜组织苏木精染色检测角膜上皮变化情况。结果:实验组NOD小鼠泪液分泌量随造模时间而逐渐降低,正常对照组未有明显变化。实验组的结膜杯状细胞体积变大,在造模后的第1d,杯状细胞密度较正常对照组减少(P=0.008),从造模后第7d开始,随时间延长,实验组杯状细胞数量逐渐减少,且较同一时间点正常对照组显著减少(均P<0.001)。此外,观察两组第10d的角膜上皮情况,实验组NOD小鼠角膜上皮层变薄,部分角膜上皮细胞变性、基底细胞水肿。结论:初步建立了NOD小鼠干眼模型,其眼表变化与临床上干眼症表现类似。

波前像差光路系统检测IOL倾斜和偏心对光学成像质量的影响

目的:通过波前像差光路系统探讨人工晶状体(IOL)偏心和倾斜对光学成像质量的影响。方法:在5.0mm模拟瞳孔直径下,采用实验室搭建的Hartmann-Shack IOL波前像差光路系统检测球面IOL Sensar AR40e、非球面单焦点IOL Tecnis ZA9003、非球面多焦点IOL Tecnis ZM900分别在偏中心0、0.2、0.4、0.6、0.8mm,向鼻侧和颞侧倾斜5°、10°、15°、20°、25°时对光学成像质量的影响,以高阶像差和调制传递函数(MTF)定量成像质量。结果:倾斜5°以内时,Tecnis ZA9003 MTF值高于AR40e和Tecnis ZM900,而倾斜5°、10°、15°、20°时三种IOL MTF值有显著差异。Tecnis ZA9003 IOL倾斜角度与彗差呈显著正相关(r=0.842,P<0.001),与球面像差无显著相关性(r=0.229,P=0.241)。偏心0.6、0.8mm时三种IOL MTF值有显著差异(均P<0.001),Tecnis ZM900偏心大于0.4mm时成像质量明显下降。结论:具有-0.27μm球差的非球面IOL倾斜度小于5°,偏心小于0.4mm时可获得比球面IOL更好的光学成像质量。Tecnis ZM900 IOL偏心大于0.4mm时较球面和非球面IOL的光学成像质量降低。

行FS-LASIK近视患者的Kappa角动态分布特征及其相关性分析

目的:探讨行飞秒激光联合准分子激光原位角膜磨镶术(FS-LASIK)近视患者的瞳孔大小和中心的动态变化分布,角膜共轴反光点的偏心量分布规律及其相关性分析。方法:本研究采用回顾性研究,选择2019-01/05在延边大学附属医院眼科行FS-LASIK的患者225例407眼,术前采用角膜地形图仪测量瞳孔的大小和中心位置,准分子激光机记录患者仰卧位时瞳孔中心与角膜共轴反光点之间的偏移量(P-Dist)。结果:术前角膜中心与瞳孔中心之间的偏移量分布平均为0.322±0.194mm,262眼(64%)≤0.40mm;P-Dist分布平均为0.225±0.102mm,326眼(80%)≤0.30mm。角膜共轴反光点主要偏向角膜中心的颞上侧138眼(34%)。暗光条件下左眼X轴:-0.061±0.084mm,右眼X轴:-0.016±0.059mm(P=0.002)(左眼暗光下向颞侧位移)。角膜横径(WTW)与瞳孔直径变化呈正相关性(r=0.270,P<0.001)。结论:左眼应调整切削中心偏向颞侧0.061mm以内的位置上,角膜横径偏大的患者,术中尽量维持较暗光线环境,以便提高瞳孔匹配的效率。

Dynamic stress–strain properties of Ti–Al–V titanium alloys with various element contents

A series of Ti–Al–V titanium alloy bars with nominal composition Ti–7Al–5V ELI,Ti–5Al–3V ELI,commercial Ti–6Al–4V ELI and commercial Ti–6Al–4V were prepared.These alloys were then heat treated to obtain bimodal or equiaxed microstructures with various contents of primary a phase.Dynamic compression properties of the alloys above were studied by split Hopkinson pressure bar system at strain rates from 2,000 to 4,000 s-1.The results show that Ti–6Al–4V alloy with equiaxed primary a(ap)volume fraction of 45 vol%or 67 vol%exhibits good dynamic properties with high dynamic strength and absorbed energy,as well as an acceptable dynamic plasticity.However,all the Ti53ELI specimens and Ti64ELI specimens with ap of 65 vol%were not fractured at a strain rate of4,000 s-1.It appears that the undamaged specimens still have load-bearing capability.Dynamic strength of Ti–Al–V alloy can be improved as the contents of elements Al,V,Fe,and O increase,while dynamic strain is not sensitive to the composition in the appropriate range.The effects of primary alpha volume fraction on the dynamic properties are dependent on the compositions of Ti–Al–V alloys.

Research progress on microstructure evolution and hot processing maps of high strength β titanium alloys during hot deformation

High strength β titanium alloys are widely used in large load bearing components in the aerospace field. At present, large parts are generally formed by die forging. Different initial microstructures and deformation process parameters will significantly affect the flow behavior. To precisely control the microstructures, researchers have conducted many studies to analyze the microstructure evolution law and deformation mechanism during hot compression. This review focuses on the microstructure evolution of high strength β titanium alloys during hot deformation, including dynamic recrystallization and dynamic recovery in the single-phase region and the dynamic evolution of the α phase in the two-phase region. Furthermore, the optimal hot processing regions, instability regions,and the relationship between the efficiency of power dissipation and the deformation mechanism in the hot processing map are summarized. Finally, the problems and development direction of using hot processing maps to optimize process parameters are also emphasized.

Modeling hot deformation behavior of low-cost Ti-2Al-9.2Mo-2Fe beta titanium alloy using a deep neural network

Ti-2 Al-9.2 Mo-2 Fe is a low-cost β titanium alloy with well-balanced strength and ductility, but hot working of this alloy is complex and unfamiliar. Understanding the nonlinear relationships among the strain,strain rate, temperature, and flow stress of this alloy is essential to optimize the hot working process.In this study, a deep neural network(DNN) model was developed to correlate flow stress with a wide range of strains(0.025–0.6), strain rates(0.01–10 s^-1) and temperatures(750–1000℃). The model, which was tested with 96 unseen datasets, showed better performance than existing models, with a correlation coefficient of 0.999. The processing map constructed using the DNN model was effective in predicting the microstructural evolution of the alloy. Moreover, it led to the optimization of hot-working conditions to avoid the formation of brittle precipitates(temperatures of 820–1000℃ and strain rates of 0.01-0.1 s^-1).

GNPs/Al nanocomposites with high strength and ductility and electrical conductivity fabricated by accumulative roll-compositing

Aluminum matrix composites(AMCs) reinforced with graphene nanoplatelets(GNPs) were fabricated by using an accumulative roll-compositing(ARC) process.Microstructure, mechanical and electrical properties of the nanostructured AMCs were characterized. The results showed that small addition(0.2 vol% and 0.5 vol%) of GNPs can lead to a simultaneous increase in the tensile strength and ductility of the GNPs/Al nanocomposites, as compared with the same processed pure Al. With increasing GNPs content, the tensile strength of the GNPs/Al nanocomposites can be enhanced to 387 MPa with retained elongation of 15%. Meanwhile, the GNPs/Al nanocomposites exhibited a good electrical conductivity of77.8%–86.1% that of annealed pure Al. The excellent properties(high strength, high ductility and high conductivity) of the GNPs/Al are associated with the particular ARC process, which facilitates the uniform dispersion of GNPs in the matrix and formation of ultrafine-grained Al matrix. The strengthening and toughening of the GNPs/Al nanocomposites were discussed considering different mechanisms and the unique effect of GNPs.

Non-linear Radical Additions-Coupling Polymerization of Monovinyl Monomers towards Polymer Networks: Theory, Tunability and Heritable Architecture

Exploring new polymerization strategy for current available monomers is a big challenge in polymer science. Here we re-investigate radical polymerization of monovinyl monomer(MVM) initiated by uniform branched polyfunctional initiator(PFI), which is termed non-linear radical additions-coupling polymerization(NLRAs CP). In NLRAs CP, both addition and coupling reactions of radical contribute to the construction of the polymer chains, which leads to continuous growth of branch topology. Theoretical analysis of NLRAs CP predicts that the gelation is determined by the functionality of PFI(a), the extent of initiation of the PFI(q) and the termination factor of radical(φ). NLRAs CPs of styrene and methyl methacrylate promoted by Cu(0)/MeTREN or Mn_(2)(CO)_(10)/visible light were conducted. After the cleavage of incorporated PFI fragment or junctions in the network, the network was transformed to linear chains having almost the same structure as segmental chains in the precursor network. This allows the reverse deducing the network structure from its cleaved products. It has been proven that NLRAs CP includes stepwise initiation of PFI, chain-growth of segmental chains and successive endlinking of macroradicals derived from PFI. The three parameters related to the gelation process, a, q and φ, were adjusted via binary PFI, the feed ratio of [Mn_(2)(CO)_(10)]/[PFI] and addition of non-homopolymerizable comonomer respectively. The minimum values of a and q, and the minimum amount of comonomer required for gelation were determined,which can be applied to estimate φ of various macroradicals. NLRAs CP opens a general and facile strategy for synthesis of a variety of polymer networks with heritable architecture by one-pot polymerization of various MVMs.

Thermal stability of bimodal grain structure in a cobalt-based superalloy subjected to high-temperature exposure

The present work investigates the thermal stability and mechanical properties of a Co-20 Cr-15 W-10 Ni(wt%) alloy with a bimodal grain(BG) structure.The BG structure consisting of fine grains(FGs) and coarse grains(CGs) is thermally stable under high-temperature exposure treatments of 760℃ for 100 h and 870℃ for 100-1000 h.The size of both FGs and CGs remains no significant changes after thermal exposure treatments.The microstructural stability is associated with the slow kinetics of grain growth and the pinning of carbides.The thermal stability enables to maintain the BG structures,leading to the same mechanical properties as the sample without thermal exposure treatment.In particular,the BG alloy samples after thermal exposure treatment exhibit superior mechanical properties of both high strength and high ductility compared to the unimodal grain(UG) structured ones.The BG structure of the alloy samples after thermal exposure is capable of avoiding severe loss of ductility and retaining high strength.More specifically,the ductility of the BG alloy samples after thermal exposure treatments of 870℃ for 500-1000 h is ten times higher(44.6% vs.3.5% and 52.6% vs.5.0%) than that of the UG ones.The finding in the present work may give new insights into high-temperature applications of the Co-20 Cr-15 W-10 Ni alloy and other metallic materials with a BG structure.

Microstructure and mechanical properties of a new high-strength and high-toughness titanium alloy

In order to develop a new titanium alloy with a good combination of strength-ductility-toughness,a nearbeta titanium alloy was designed based on the already widely used Ti-1023 alloy.To avoid beta fleck occurring in the microstructure,the new Ti-Al-Fe-V(Cr,Zr) alloy has been made through decreasing the content of Fe,based on molybdenum equivalency and Bo-Md molecular orbital method(a method for new alloy designing based on the molecular orbital calculating).After primary design computation,Ti-Al-Fe-V(Cr,Zr) alloy was optimized as Ti-3Al-4.5Cr-1Fe-4V-1Zr finally.The microstructure and tensile properties of this alloy subjected to several commonly used heat treatments were investigated.The results show that the tensile strength of the alloy after solution treated below the β-transus temperature comes between 850 and 1100 MPa,with elongation in the range of 12.5 %-17.0 %.In solution-treated and solution-aged samples,a low-temperature aging at 500 ℃ results in the precipitation of finer α phase.With the increase in aging temperature,the secondary α phase becomes coarser and decreases in amount.Thus,it will lead to the increase in tensile ductility,but reduction in strength.Eventually,after modulated aging treatment,the alloy can obtain highstrength level with acceptable ductility.The tensile strength of the alloy can achieve 1273 MPa,with an elongation of 11.0 %.At the same time,the fracture toughness(K_(IC)) of the alloy achieves 83.8 MPa·m^(1/2).It is obvious that the newly designed alloy has achieved a good blend of strength-ductility-toughness.

Morphology control of magnetic properties in cobalt nanowires

Cobalt nanowires with different shapes and sizes were synthesized by reduction of carboxylate salts of Co^(Ⅱ) in 1,2-butanediol using a solvothermal chemical process.The well-crystallized Co nanowires with hexagonal closepacked(hep) phase are observed and the(002) crystalline direction is along the long axis of nano wires.The morphology control is strongly dependent on the reaction parameters.By varying the amount of capping agent in proper ranges,the effect of reaction parameters on controlling the size and shape of Co nanowires is demonstrated.With the amount of capping agent increasing,the aspect ratio of Co nanowires increases remarkably.However,the magnetic measurement of cobalt nanowires shows that the coercivity of the Co nanocrystals does not increase with the increase in aspect ratio monotonously,which suggests that the tip shape and micros tructure also play an important role in the magnetization reversal process of the Co nanocrystals,and the aspect ratio plays a much less role as the ratio value exceeds 11.To further understand the effect of size on the magnetic properties in the Co nanowires,micromagnetic simulations were performed,which confirms that the magnetic properties are barely affected by the aspect ratio larger than 10.The highest coercivity of624 kA·m^(-1) is obtained for ellipsoid nano wires with a mean length of 200 nm,which also displays a strong magnetic anisotropy.As a result,the highest energy product of the wires reaches 248 kJ·m^(-3).

Research progress on hot deformation behavior of high-strength β titanium alloy: flow behavior and constitutive model

High-strength β titanium alloys represented by near β titanium alloy and metastable β titanium alloy are preferred materials for large-scale load-carrying structures.In order to achieve the precise regulation of microstructure in the deformation process, massive efforts have been made to study the flow behavior and microstructure evolution of βtitanium alloy in the hot deformation process. This paper reviews the flow behavior of high-strength titanium alloy,including the effects of initial microstructure, deformation process parameters, work hardening, and dynamic softening on flow stress. Furthermore, the effects of deformation process parameters on the apparent activation energy for deformation and strain rate sensitivity coefficient are analyzed. The discontinuous yield phenomenon is discussed,and the constitutive models of flow stress are summarized.Furthermore, some microstructural evolution models are reviewed. Finally, the development direction and difficulties of the flow behavior and constitutive model are pointed out.

Bimodal grain structures and tensile properties of a biomedical Co-20Cr-15W-10Ni alloy with different pre-strains

The influence of pre-strain on the formation of bimodal grain structures and tensile properties of a Co-20 Cr-15 W-10 Ni alloy was investigated.The bimodal grain structures consist of fine grains(FGs;2-3μm in diameter)and coarse grains(CGs;8-16μm in diameter),which can be manipulated by changing the pre-strain(ε=0.3-0.7)and annealing temperatures(1000-1100℃).High pre-strain applied in the samples can intensify the plasticity heterogeneity through increasing the total dislocation density and the local volumes of high-density dislocations.This can essentially result in finer FGs,a higher FG volume fraction,and overall grain refinement in the samples after annealing.High-temperature essentially increases both the size and volume fraction of CGs,leading to an increase in the average grain size.The tensile test suggests that the bimodal grain structured samples exhibited both high strength and ductility,yield strengths of621-877 MPa and ultimate tensile strengths of1187-1367 MPa with uniform elongations of 55.0%-71.4%.The superior strength-ductility combination of the samples arises from the specific deformation mechanisms of the bimodal grain structures.The tensile properties strongly depend on the size ratio and volume fraction of FGs/CGs in addition to the average grain size in the bimodal grain structures.The grain structures can be modified via changing the pre-strain and annealing temperature.