Experimental Study of Thin Wall Milling Chatter Stability Nonlinear Criterion

AbstractThe nonlinear dynamic behavior of milling process has been accompanied by the entire cutting process. In order to accurately determine and predict chatter stability of machining process, this article studied at both ends of the fixed thin part nonlinear criterion of milling chatter stability with experimental method. The experiment takes the vibration signal of thin part as the study object. And it analyses the vibration signal of different processing parameters based on the phase plane method, Poincare method and spectral analysis. Then, the relationship between the maximum Lyapunov exponent and the spindle speed and milling depth changes is discussed. Finally, taking the largest Lyapunov exponent as the criterion, the study determines the chatter stability domain of milling by using contour method. The comparative analysis is based on the milling chatter stability domain which obtained from the full discrete method. The experiments obtained the nonlinear stability criterion of aviation aluminium alloy 7075-T6 thin part

Compound Bieshe Kang’ai inhibits proliferation and induces apoptosis in HCT116 human colorectal cancer cells

Purpose: To study the effect of Compound Bieshe Kang’ai (CBK) on proliferation and apoptosis in colorectal cancer cells.Methods: HCT116 colorectal cancer cells and FHs 74 Int intestinal cells were treated with CBK, followed by determination of cell proliferation with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Caspase-9 and caspase-3 activities as well as protein expressions of Bcl-2 and BAX, and mRNA levels of caspase-9, caspase-3, Bcl-2 and BAX in HCT116 cells were evaluated, followed by examination of the morphological alterations of HCT116 cells with Hoechst 33342 staining.Results: CBK suppressed proliferation of HCT116 cells in a concentration- and time-dependent pattern, without cytotoxicity to FHs 74 Int cells. CBK also elevated caspase-9 and caspase-3 activities, mitigated protein translation of Bcl-2 and augmented that of BAX. It also enhanced mRNA transcriptions of caspase-9, caspase-3 and BAX, but decreased that of Bcl-2 in HCT116 cells in a  concentrationdependent manner, as well as induced cancer cell shrinkage, nuclear fragmentation and chromatin condensation.Conclusion: The findings highlight CBK as a promising therapeutic agent for colorectal cancers, by retarding proliferation and inducing apoptosis in cancer cells.Keywords: Apoptosis, BAX, Bcl-2, Cancer, Caspase, Compound Bieshe Kang’ai, Chromatin condensation, Nuclear fragmentatio

Discriminant Analysis of Jiang-Flavor Baijiu of Different Grades by Gas Chromatography-Mass Spectrometry and Electronic Tongue

Gas chromatography-mass spectrometry (GC-MS) and electronic tongue were used to quantitatively determine the volatile compounds and taste indices of 21 Jiang-flavor baijiu samples of different grades. These samples were differentiated by chemometrics, and key differential compounds among grades were identified. Finally, a discriminant model was established by machine learning. The results showed that there were differences in the contents of volatile compounds in Jiang-flavor baijiu of three grades, indicating the feasibility of further discriminant analysis. The total content of flavor compounds in second-grade baijiu (4 908 mg/L) was significantly lower than that in premium-grade (6 583 mg/L) and first-grade baijiu (8 254 mg/L), while the proportion of several esters responsible for floral and fruity aromas in total esters showed a decreasing trend as the grade decreased. Partial least squares-discriminant analysis (PLS-DA) identified 16 key differential compounds represented by ethyl palmitate and acetic acid. The results of electronic tongue showed that the taste indexes of premium-grade baijiu were more consistent, with lower bitterness and astringency aftertaste. The taste indexes of second-grade baijiu showed significant intersample differences. Principal component analysis (PCA) showed clear discrimination of Jiang-flavor baijiu of different grades according to their taste indexes. The above results provide a basis for the establishment of Jiang-flavor baijiu quality system. Four discriminant models were established based on 25 differential compounds and taste indexes identified. The accuracy of all models was higher than 90%, and the support vector machine (SVM) model performed best, with an accuracy of 100%

Observation of whistler wave instability driven by temperature anisotropy of energetic electrons on EXL-50 spherical torus

Electromagnetic modes in the frequency range of 30-120MHz were observed in electron cyclotron wave (ECW) steady state plasmas on the ENN XuanLong-50 (EXL-50) spherical torus. These modes were found to have multiple bands of frequencies proportional to the Alfv\'en velocity. This indicates that the observed mode frequencies satisfy the dispersion relation of whistler waves. In addition, suppression of the whistler waves by the synergistic effect of Lower Hybrid Wave (LHW) and ECW was also observed. This suggests that the whistler waves were driven by temperature anisotropy of energetic electrons. These are the first such observations (not runaway discharge) made in magnetically confined toroidal plasmas and may have important implications for studying wave-particle interactions, RF wave current driver, and runaway electron control in future fusion devices

Association of Adiponectin SNP+45 and SNP+276 with Type 2 Diabetes in Han Chinese Populations: A Meta-Analysis of 26 Case-Control Studies

Recently, many studies have reported that the SNP+45(T>G) and SNP+276(G>T) polymorphisms in the adiponectin gene are associated with type 2 diabetes (T2DM) in the Chinese Han population. However, the previous studies yielded many conflicting results. Thus, a meta-analysis of the association of the adiponectin gene with T2DM in the Chinese Han population is required. In the current study, we first determined the distribution of the adiponectin SNP+276 polymorphism in T2DM and nondiabetes (NDM) control groups. Our results suggested that the genotype and allele frequencies for SNP+276 did not differ significantly between the T2DM and NDM groups. Then, a meta-analysis of 23 case-control studies of SNP+45, with a total of 4161 T2DM patients and 3709 controls, and 11 case-control studies of SNP+276, with 2533 T2DM patients and 2212 controls, was performed. All subjects were Han Chinese. The fixed-effects model and random-effects model were applied for dichotomous outcomes to combine the results of the included studies. The results revealed a trend towards an increased risk of T2DM for the SNP+45G allele as compared with the SNP+45T allele (OR = 1.34; 95% CI, 1.11–1.62; P<0.01) in the Chinese Han population. However, there was no association between SNP+276 and T2DM (OR = 0.90; 95% CI, 0.73–1.10; P = 0.31). The results of our association study showed there was no association between the adiponectin SNP+276 polymorphism and T2DM in the Yunnan Han population. The meta-analysis results suggested that the SNP+45G allele might be a susceptibility allele for T2DM in the Chinese Han population. However, we did not observe an association between SNP+276 and T2DM

Magnetoelectric interaction and transport behaviours in magnetic nanocomposite thermoelectric materials

How to suppress the performance deterioration of thermoelectric materials in the intrinsic excitation region remains a key challenge. The magnetic transition of permanent magnet nanoparticles from ferromagnetism to paramagnetism provides an effective approach to finding the solution to this challenge. Here, we have designed and prepared magnetic nanocomposite thermoelectric materials consisting of BaFe12O19 nanoparticles and Ba0.3In0.3Co4Sb12 matrix. It was found that the electrical transport behaviours of the nanocomposites are controlled by the magnetic transition of BaFe12O19 nanoparticles from ferromagnetism to paramagnetism. BaFe12O19 nanoparticles trap electrons below the Curie temperature (TC) and release the trapped electrons above the TC, playing an ‘electron repository’ role in maintaining high figure of merit ZT. BaFe12O19 nanoparticles produce two types of magnetoelectric effect—electron spiral motion and magnon-drag thermopower—as well as enhancing phonon scattering. Our work demonstrates that the performance deterioration of thermoelectric materials in the intrinsic excitation region can be suppressed through the magnetic transition of permanent magnet nanoparticles

Reduced expression of N-Myc downstream-regulated gene 2 in human thyroid cancer

<p>Abstract</p> <p>Background</p> <p><it>NDRG</it>2 (N-Myc downstream-regulated gene 2) was initially cloned in our laboratory. Previous results have shown that <it>NDRG</it>2 expressed differentially in normal and cancer tissues. Specifically, <it>NDRG</it>2 mRNA was down-regulated or undetectable in several human cancers, and over-expression of <it>NDRG</it>2 inhibited the proliferation of cancer cells. <it>NDRG</it>2 also exerts important functions in cell differentiation and tumor suppression. However, it remains unclear whether <it>NDRG</it>2 participates in carcinogenesis of the thyroid.</p> <p>Methods</p> <p>In this study, we investigated the expression profile of human <it>NDRG</it>2 in thyroid adenomas and carcinomas, by examining tissues from individuals with thyroid adenomas (n = 40) and carcinomas (n = 35), along with corresponding normal tissues. Immunohistochemistry, quantitative RT-PCR and western blot methods were utilized to determine both the protein and mRNA expression status of Ndrg2 and c-Myc.</p> <p>Results</p> <p>The immunostaining analysis revealed a decrease of Ndrg2 expression in thyroid carcinomas. When comparing adenomas or carcinomas with adjacent normal tissue from the same individual, the mRNA expression level of <it>NDRG</it>2 was significantly decreased in thyroid carcinoma tissues, while there was little difference in adenoma tissues. This differential expression was confirmed at the protein level by western blotting. However, there were no significant correlations of <it>NDRG</it>2 expression with gender, age, different histotypes of thyroid cancers or distant metastases.</p> <p>Conclusion</p> <p>Our data indicates that <it>NDRG</it>2 may participate in thyroid carcinogenesis. This finding provides novel insight into the important role of <it>NDRG2 </it>in the development of thyroid carcinomas. Future studies are needed to address whether the down-regulation of <it>NDRG</it>2 is a cause or a consequence of the progression from a normal thyroid to a carcinoma.</p

VCP/p97 is required for the timely degradation of p27 in G0/G1 to S phase transition in MCF-7 cell

VCP/p97 works as a segregase to extract the ubiquitylated proteins from protein complexes, lipid membranes and chromosomes, thereby promoting their degradation or recycling. VCP/p97 plays essential roles in ubiquitin-dependent proteasome degradation, ERAD, autophagy, endocytosis, reassembly of ER, Golgi and nuclear envelop, and cell cycle regulation. In ubiquitin dependent proteasome degradation pathway, VCP/p97, as a special ubiquitin binding-shuttle factor, is required for the successful cell cycle progression in regulating IκB, CDT-1, Aurora B, and CDC25A. Here, we studied the role of VCP/p97 in G1 to S phase transition in MCF-7 human breast cancer cells. We found that VCP/p97 knockdown or inhibition by DBeQ, a potent VCP/p97 inhibitor, decreased cell proliferating rates and reduced S phase cell percentages in asynchronized MCF-7 cells.VCP/p97 inhibition by DBeQ also arrested cells at G1 phase in synchronized MCF-7 cells. These data suggest that VCP/p97 is required for G0/G1 to S phase transition in MCF-7 cells. In addition, in either asynchronized or synchronized MCF-7 cells, VCP/p97 knockdown or DBeQ treatment resulted in the accumulation of p21 and p27, two CDK inhibitors. Moreover, p27, not p21, knockdown in MCF-7 cells rescued the defects of S phase entry caused by VCP/p97 knockdown or DBeQ treatment. Taken together, our results suggest that VCP/p97 regulates the timely degradation of p27 to promote G1 to S phase transition in MCF-7 cells.published_or_final_versionPhysiologyMasterMaster of Philosoph