Friction and wear behavior and mechanism of low carbon microalloyed steel containing Nb

Dry sliding friction and wear test of Nb containing low carbon microalloyed steel was carried out at room temperature,and the effect of Nb on the wear behavior of the steel,as welll as the mechanism was studied.Scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) were employed to analyze the morphology and composition of the worn surface,and the structure evolution of the plastic deformation layer.The carbide content and type in the steel were analyzed by the electrolytic extraction device and X-ray diffraction(XRD).The experimental results demonstrate that the addition of 0.2% Nb can refine the grain and generate Nb C to improve the wear resistance of the steel.By enhancing the load and speed of wear experiment,the wear mechanism of the test steel with 0.2% Nb changes from slight oxidation wear to severe adhesion wear and oxidation wear.Compared with the load,the increase in the rotation speed exerts a greater influence on the wear of the test steel.

Traditional Chinese medicine prescriptions and herbs for the treatment of hypothyroidism:a narrative review

The increasing prevalence of hypothyroidism,which can cause endocrine dysfunction,abnormal neurological function,and cardiovascular and cerebrovascular injuries,poses serious health problems.Thyroid hormone supplementation constitutes the current main therapeutic method for hypothyroidism,yet it has many limitations and risks and is not suitable for everyone.Therefore,it is necessary to seek alternative and complementary treatment methods.It has been proven in practice that traditional Chinese medicine(TCM)possesses multi-channel comprehensive characteristics for the treatment of hypothyroidism and has more advantages than single thyroid hormone supplementation.Through a comprehensive examination of existing literature about TCM efficacy in addressing hypothyroidism,we have meticulously consolidated the most recent research findings on prescriptions and herbal substances employed in the treatment of this condition.Furthermore,we have explicated their respective functions in the management of hypothyroidism,thereby offering valuable perspectives and recommendations for the prospective utilization of natural remedies in its treatment.

Effect of Tangweian Jianji on upper gastrointestinal remodeling in streptozotocin-induced diabetic rats

AIM:To investigate the effect of Tangweian Jianji(TWAJJ) on the biomechanical and morphometrical remodeling of the upper gastrointestinal tract in diabetic rats.METHODS:Diabetes was induced in 27 rats by injecting streptozotocin(40 mg/kg body weight),the animals were then divided into three groups(n = 9 in each group),i.e.,diabetic control(DM);high dose(10 g/kg,T1) and low dose(5 g/kg,T2).Another 10 rats acted as normal controls(Control).TWAJJ was administered by gavage once daily.Blood glucose and serum insulin levels were measured.Circumferential length,wall thickness and opening angle were measured from esophageal,duodenal,jejunal and ileal ring segments.The residual strain was calculated from the morphometric data.Step-wise distension was carried out on esophageal and jejunal segments.The obtained data on the length,diameter and pressure changes were then used to calculate the circumferential and longitudinal stresses and strains.Real-time reverse transcription polymerase chain reaction was used to detect the receptor of advanced glycation end-products(RAGE) mRNA level in jejunal tissues.RESULTS:At the end of the experiment,the blood glucose level was significantly higher and the serum insulin level was significantly lower in DM,T1 and T2 groups than in the control group(Glucose:30.23 ± 0.41 mmol/L,27.48 ± 0.27 mmol/L and 27.84 ± 0.29 mmol/L vs 5.05 ± 0.04 mmol/L,P = 1.65 × 10-16,P = 5.89 × 10-19 and P = 1.63 × 10-18,respectively;Insulin:1.47 ± 0.32 g/L,2.66 ± 0.44 g/L,2.03 ± 0.29 g/L and 4.17 ± 0.54 g/L,P = 0.0001,P = 0.029 and P = 0.025,respectively).However,these levels did not differ among the DM,T1 and T2 groups.The wet weight per unit length,wall thickness and opening angle of esophageal and intestinal segments in the DM group were significantly higher than those in the control group(from P = 0.009 to P = 0.004).These parameters in the T1 group were significantly lower than those in the DM group(wet weight,duodenum:0.147 ± 0.003 g/cm vs 0.158 ± 0.001 g/cm,P = 0.047;jejunum,0.127 ± 0.003 g/cm vs 0.151 ± 0.002 g/cm,P = 0.017;ileum,0.127 ± 0.004 g/cm vs 0.139 ± 0.003 g/cm,P = 0.046;wall thickness,esophagus:0.84 ± 0.03 mm vs 0.94 ± 0.02 mm,P = 0.014;duodenum:1.27 ± 0.06 mm vs 1.39 ± 0.05 mm,P = 0.031;jejunum:1.19 ± 0.07mm vs 1.34 ± 0.04 mm,P = 0.047;ileum:1.09 ± 0.04 mm vs 1.15 ± 0.03 mm,P = 0.049;opening angle,esophagus:112.2 ± 13.2 vs 134.7 ± 14.7,P = 0.027;duodenum:105.9 ± 12.3 vs 123.1 ± 13.1,P = 0.046;jejunum:90.1 ± 15.4 vs 115.5 ± 13.3,P = 0.044;ileum:112.9 ± 13.4 vs 136.1 ± 17.1,P = 0.035).In the esophageal and jejunal segments,the inner residual stain was significantly smaller and the outer residual strain was larger in the DM group than in the control group(P = 0.022 and P = 0.035).T1 treatment significantly restored this biomechanical alteration(P = 0.011 and P = 0.019),but T2 treatment did not.Furthermore,the circumferential and longitudinal stiffness of the esophageal and jejunal wall increased in the DM group compared with those in the control group.T1,but not T2 treatment,significantly decreased the circumferential wall stiffness in the jejunal segment(P = 0.012) and longitudinal wall stiffness in the esophageal segment(P = 0.023).The mRNA level of RAGE was significantly decreased in the T1 group compared to that in the DM group(P = 0.0069).CONCLUSION:TWAJJ(high dose) treatment partly restored the morphometric and biomechanical remodeling of the upper gastrointestinal tract in diabetic rats.

Wnt/β-catenin pathway might underlie the MET in transdifferentiation from MSC to MSC-derived neuron

Objective: To observe MET-associated alteration during the trans-differentiation from MSCs to neuron-like cells, and to explore the possible molecular mechanism. Methods: Bone marrow MSCs were isolated from rat femur and purified in continuous cell culture. After induced differentiation to neuron-like cells by the combination of butylated hydroxyanisole(BHA)and dimethyl sulfoxide(DMSO), cells were tested by comparative polymerase chain reaction(PCR) for the relative expression of MET biomarkers and transcription factors, and for cell cycle by flow cytometry. Meanwhile, target genes of Wnt/β-catenin pathway were also analyzed by comparative PCR to determine the possible involvement. Results: In MSC-induced neuron-like cells, MET-associated transcription factors such as Snail, Slug, ZEB1, ZEB2, and Twist were significantly attenuated in expression level. The Mesenchymal marker Vimentin expression level was increased. Membrane protein E-cad was slightly down-regulated, while N-cad level was marginally elevated. Percentage of proliferating cells(S phase in cell cycle) markedly shrank from 40.42% for MSCs to 6.76% for MSC-derived neuron. Additionally, Wnt/β-catenin target genes β-catenin and c-myc were decreasingly expressed. Conclusion: Chemically induced trans-differentiation from MSC to neuron caused similar MET-featured alteration in gene expression and proliferation to known MET, which might be underlied by deactivation of Wnt/ β-catenin pathway.

Effect of licartin combined with pirarubicin TACE on apoptosis and epithelial-mesenchymal transition in unresectable liver cancer tissue

Objective:To study the effect of licartin combined with pirarubicin transcatheter arterial chemoembolization (TACE) on apoptosis and epithelial - mesenchymal transition in unresectable liver cancer tissue.Methods: Patients with unresectable liver cancer who were treated in Navy General Hospital between May 2014 and October 2016 were selected and randomly divided into two groups, the licartin group received licartin combined with TACE therapy, and control group received TACE therapy alone. The expression of tumor suppressor genes, autophagy marker genes and epithelial-mesenchymal transition marker genes in liver cancer lesions were determined before and after treatment.Results: After operation, RNF180, EBLN2, ALKBH5, Merlin, Beclin-1, LC3-II, TRAF-6 and E-cadherin protein expression in liver cancer lesions of both groups of patients were significantly higher than those before operation while Shh, Gli1, Snail, Twist, N-cadherin and Vimentin protein expression were significantly lower than those before operation, and RNF180, EBLN2, ALKBH5, Merlin, Beclin-1, LC3-II, TRAF-6 and E-cadherin protein expression in liver cancer lesions of licartin group were significantly higher than those of control group while Shh, Gli1, Snail, Twist, N-cadherin and Vimentin protein expression were significantly lower than those of control group.Conclusions:Licartin combined with pirarubicin TACE for unresectable liver cancer can more effectively induce apoptosis and autophagy, and inhibit epithelial-mesenchymal transition.

Assessment of the efficacy and safety of bronchial artery perfusion chemotherapy combined with high-frequency hyperthermia for advanced non-small cell lung cancer

Objective:To study the efficacy and safety of bronchial artery perfusion chemotherapy combined with high-frequency hyperthermia for advanced non-small cell lung cancer. Methods:Patients with advanced non-small cell lung cancer who were treated in Navy General Hospital between May 2014 and October 2016 were selected and randomly divided into two groups, the observation group received bronchial arterial infusion chemotherapy combined with high-frequency hyperthermia, and the control group received bronchial arterial infusion chemotherapy. Before and after treatment, the expression of tumor activity indexes and liver and kidney function indexes in serum as well as and proliferation and invasion genes in tumor lesions were detected respectively.Results: 5 d and 7 d after treatment, serum CEA, MIF, CYFRA21-1 and HE4 levels of both groups of patients were significantly lower than those before treatment and serum CEA, MIF, CYFRA21-1 and HE4 levels of observation group were significantly lower than those of control group;7 d after treatment, MEF2D, c-myc, Survivin, Bcl-2, Vimentin, N-cadherin and Slug expression in tumor lesions of both groups of patients were significantly lower than those before treatment and MEF2D, c-myc, Survivin, Bcl-2, Vimentin, N-cadherin and Slug expression in tumor lesions of observation group were significantly lower than those of control group;serum Scr, BUN, ALT and AST levels were not significantly different between two groups of patients before and after treatment. Conclusion:Bronchial artery perfusion chemotherapy combined with high-frequency hyperthermia for advanced non-small cell lung cancer can significantly inhibit the tumor proliferation and invasion and is with ideal safety.

Detection of ryanodine receptor target-site mutations in diamide insecticide-resistant Spodoptera frugiperda in China

Spodoptera frugiperda(Lepidoptera:Noctuidae)is a widely distributed pest of corn.Since it invaded China in 2018,it has caused serious damage to local corn production.Chlorantraniliprole,an anthranilic diamide insecticide,has been widely used to control lepidopteran pests.Tetrachloropyramid is a new allosteric modulator insecticide devel-oped based on chlorantraniliprole,so it has a similar mechanism and insecticidal effect.In this study,we investigated resistance levels to chlorantraniliprole and tetrachloropyramid in S.frugiperda from 13 populations in China.Among the populations tested,the relative highest resistance to chlorantraniliprole occurred in the Guangzhou population,and the most susceptible to chlorantraniliprole was found in the Wuhan population.The lethal dosage LD50 value of the Guangzhou population against chlorantraniliprole was 27.8-fold higher than that of the Wuhan population.Minimal differences were observed among 5".frugiperda populations in terms of sensitivity to tetrachloropyramid.Heterozygous mutations at the 14734 site of the ryanodine receptor(RyR)were found,while no mutations were found in the G4891 site.The mutations were detected in only two of the 786 individuals analyzed one from the Qinzhou population and other from the Anshun population(frequency below 2%in both cases).There were no significant differences in the expression levels of RyR between Guangzhou and Wuhan populations.In summary,our results indicate that:(i)S.frugiperda has low resistance levels to diamide insecticides in China;and(ii)the differences in relative resistance among the 13 populations analyzed are not caused by the mutations in RyR or the expression of RyR.

Microstructure and properties evolution of Nb-bearing medium Cr wear-resistant cast steel during heat treatment

The effect of quenching temperature and cooling conditions on the microstructure and mechanical properties of a 0.2%Nb medium chromium wear-resistant cast steel was investigated.The microstructure,carbides and volume fraction of retained austenite were characterized using the optical microscope,scanning electron microscope,transmission electron microscope and X-ray diffraction.The influence of heat treatment on hardness,impact toughness and tensile properties of test steel was studied.It can be observed that lath martensite can be obtained under the condition of air cooling and oil cooling upon austenitizing in the range of 900–1020℃.Total carbide content of 0.2–1.1 wt.%under air cooling is more than that under oil cooling due to the lower cooling rate.Nb6C5,M23C6 and M7C3 were found at lower austenitizing temperature,of which niobium carbide mostly located at grain boundaries,while chromium carbides were uniformly distributed in the matrix with the size of 20–50 nm.The chromium carbides are basically dissolved into the matrix in test steel austenitized at 1020°C.Meanwhile,the negligible growth of prior austenite grain size is achieved.Specimen austenitized at 1020℃ and cooled in air+tempered at 200℃ has a best combination of hardness,plasticity and tensile strength due to fine grain size and more amount of retained austenite.Under this condition,the hardness is 58 HRC,the impact toughness is 22.92 J/cm^(2),and the tensile strength is 1136.9 MPa.

Neural Parse Combination

Analyzing the syntactic structure of natural languages by parsing is an important task in artificial intelligence. Due to the complexity of natural languages, individual parsers tend to make different yet complementary errors. We propose a neural network based approach to combine parses from different parsers to yield a more accurate parse than individual ones. Unlike conventional approaches, our method directly transforms linearized candidate parses into the ground-truth parse. Experiments on the Penn English Treebank show that the proposed method improves over a state-of-the-art parser combination approach significantly.