134 research outputs found

    Describing Strong Correlation with Block-Correlated Coupled Cluster Theory

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    A block-correlated coupled cluster (BCCC) method based on the generalized valence bond (GVB) wave function (GVB-BCCC in short) is proposed and implemented at the ab initio level, which represents an attractive multireference electronic structure method for strongly correlated systems. The GVB-BCCC method is demonstrated to provide accurate descriptions for multiple bond breaking in small molecules, although the GVB reference function is qualitatively wrong for the studied processes. For a challenging prototype of strongly correlated systems, tridecane with all 12 single C-C bonds at various distances, our calculations have shown that the GVB-BCCC2b method can provide highly comparable results as the density matrix renormalization group method for potential energy surfaces along simultaneous dissociation of all C-C bonds

    Many-Body-Expansion Based on Variational Quantum Eigensolver and Deflation for Dynamical Correlation

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    In this study, we utilize the many-body expansion (MBE) framework to decompose electronic structures into fragments by incrementing the virtual orbitals. Our work aims to accurately solve the ground and excited state energies of each fragment using the variational quantum eigensolver and deflation algorithms. Although our approach is primarily based on unitary coupled cluster singles and doubles (UCCSD) and a generalization thereof, we also introduce modifications and approximations to conserve quantum resources in MBE by partially generalizing the UCCSD operator and neglecting the relaxation of the reference states. As a proof of concept, we investigate the potential energy surfaces for the bond-breaking processes of the ground state of two molecules (H2O\rm H_2O and N2\rm N_2) and calculate the ground and excited state energies of three molecules (LiH, CH+^+, and H2O\rm H_2O). The results demonstrate that our approach can, in principle, provide reliable descriptions in all tests, including strongly correlated systems, when appropriate approximations are chosen. Additionally, we perform model simulations to investigate the impact of shot noise on the total MBE energy and show that precise energy estimation is crucial for lower-order MBE fragments

    High Expression of DNMT1 was Correlated with beta-catenin Accumulation and Malignant Phynotype of Lung Squamous Cell Carcinoma and Adenocarcinoma

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    Background and objective DNA methyltransferase 1 (DNMT1) is one of the important molecules regulating DNA methylation. The abnormal expression of DNMT1 was associated with the methylation and inactivation of tumor suppressor gene and tumorigenesis. The aim of this study is to clarify the difference of DNMT1 expression between lung cancer tissues and corresponding normal lung tissues, to analyze the relationships between DNMT1 expression and clinicopathologic characteristics of lung squamous cell carcinoma and adenocarcinoma, and to investigate the correlation between the expressions of DNMT1 and Ξ²-catenin. Methods The expressions of DNMT1 and Ξ²-catenin were examined in 84 lung squamous cell carcinoma and adenocarcinoma tissues and corresponding normal lung tissues using tissue microarray and immunohistochemistry. Results The average positive rate of DNMT1 was significantly higher in 84 lung cancer tissues [(58.04Β±35.07)%] than that in corresponding normal lung tissues [(6.88Β±10.26)%](t=12.835, P < 0.001). The high expression of DNMT1 was positively correlated with adenocarcinoma histological type (r=0.365, P=0.001), poor differentiation (r=0.253, P=0.021) and lymph node metastasis (r=0.246, P=0.024) in lung cancer. The expression of DNMT1 was significantly correlated with the cytoplasmic expression of Ξ²-catenin (r=0.571, P < 0.001). Conclusion The high expression of DNMT1 was a common phenomenon in lung squamous cell carcinoma and adenocarcinoma. The high expression of DNMT1 was correlated with the malignant phynotype of lung cancer. DNMT1 may express coordinately with Ξ²-catenin in lung cancer

    Investigation on Internal Short Circuit Identification of Lithium-Ion Battery Based on Mean-Difference Model and Recursive Least Square Algorithm

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    Electric vehicles powered by lithium-ion batteries take advantages for urban transportation. However, the safety of lithium-ion battery needs to be improved. Self-induced internal short circuit of lithium-ion batteries is a serious problem which may cause battery thermal runaway. Accurate and fast identification of internal short circuit is critical, while difficult for lithium-ion battery management system. In this study, the influences of the parameters of significance test on the performance of an algorithm for internal short circuit identification are evaluated experimentally. The designed identification is based on the mean-difference model and the recursive least square algorithm. First, the identification method is presented. Then, two characteristic parameters are determined. Subsequently, the parameters of the significance calculation are optimized based on the measured data. Finally, the effectiveness of the method for the early stage internal short circuit detection is studied by an equivalent experiment. The results indicate that the detection time can be shortened significantly via a proper configuration of the parameters for the significance test

    CCL21/CCR7 Promotes G2/M Phase Progression via the ERK Pathway in Human Non-Small Cell Lung Cancer Cells

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    C-C chemokine receptor 7 (CCR7) contributes to the survival of certain cancer cell lines, but its role in the proliferation of human non-small cell lung cancer (NSCLC) cells remains vague. Proliferation assays performed on A549 and H460 NSCLC cells using Cell Counting Kit-8 indicated that activation of CCR7 by its specific ligand, exogenous chemokine ligand 21 (CCL21), was associated with a significant linear increase in cell proliferation with duration of exposure to CCL21. The CCL21/CCR7 interaction significantly increased the fraction of cells in the G2/M phase of the cell cycle as measured by flow cytometry. In contrast, CCL21/CCR7 had no significant influence on the G0/G1 and S phases. Western blot and real-time PCR indicated that CCL21/CCR7 significantly upregulated expression of cyclin A, cyclin B1, and cyclin-dependent kinase 1 (CDK1), which are related to the G2/M phase transition. The expression of cyclin D1 and cyclin E, which are related to the G0/G1 and G1/S transitions, was not altered. The CCL21/CCR7 interaction significantly enhanced phosphorylation of extracellular signal-regulated kinase (P-ERK) but not Akt, as measured by Western blot. LY294002, a selective inhibitor of PI3K that prevents activation of the downstream Akt, did not weaken the effect of CCL21/CCR7 on P-ERK. Coimmunoprecipitation further confirmed that there was an interaction between P-ERK and cyclin A, cyclin B1, or CDK1, particularly in the presence of CCL21. CCR7 small interfering RNA or PD98059, a selective inhibitor of MEK that disrupts the activation of downstream ERK, significantly abolished the effects of exogenous CCL21. These results suggest that CCL21/CCR7 contributes to the time-dependent proliferation of human NSCLC cells by upregulating cyclin A, cyclin B1, and CDK1 potentially via the ERK pathway

    Comparison of Two Methods for Osmolality Determination of Foods for Special Dietary Uses

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    A total of 46 samples from nine types of commercially available foods for special dietary uses were collected for osmolality measurement by a freezing point and a dew point osmometer, and the differences between the two methods were analysed. The results showed that the detection range of the freezing point osmometer was 195–763 mOsmol/kg with relative standard deviation (RSD) of 0.20%–4.08%, and the detection range of the dew point osmometer was 197–649 mmol/kg with RSD of 0.00%–3.66%. It was found that different reconstitution methods had a significant effect on the determination results, and the temperature of the solution also affected the parallelism of the determination results. Statistical analysis using t-test showed that there were significant differences between the results of the two methods for each of 31 samples. It was inferred from the experiments that whether the sample solution reached an ideal dilute solution state was the major factor affecting the significant difference between both methods. This study provides a theoretical basis for further research on the detection of osmolality in foods for special dietary uses, and highlights some key issues that need urgent attention in the design and production of foods for special dietary uses

    Overexpression of CARMA3 in Non-Small-Cell Lung Cancer Is Linked for Tumor Progression

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    We aimed to investigate the clinical significance of the expression of novel scaffold protein CARMA3 in non-small-cell lung cancer (NSCLC) and the biological function of CARMA3 in NSCLC cell lines. We observed moderate to high CARMA3 staining in 68.8% of 141 NSCLC specimens compared to corresponding normal tissues. The overexpression of CARMA3 was significantly correlated with TNM stage (Pβ€Š=β€Š0.022) and tumor status (Pβ€Š=β€Š0.013). CARMA3 upregulation also correlated with a shorter survival rate of patients of nodal status N0 (Pβ€Š=β€Š0.042)as well as the expression of epidermal growth factor receptor (EGFR) (Pβ€Š=β€Š0.009). In EGFR mutation positive cases, CARMA3 expression was much higher (87.5%) compared to non-mutation cases (66.1%). In addition, we observed that knockdown of CARMA3 inhibits tumor cell proliferation and invasion, and induces cell cycle arrest at the boundary between the G1 and S phase. We further demonstrated a direct link between CARMA3 and NF-ΞΊB activation. The change of biological behavior in CARMA3 knockdown cells may be NF-ΞΊB-related. Our findings demonstrated, for the first time, that CARMA3 was overexpressed in NSCLC and correlated with lung cancer progression, EGFR expression, and EGFR mutation. CARMA3 could serve as a potential companion drug target, along with NF-kB and EGFR in EGFR-mutant lung cancers

    Expression of p130cas, E-cadherin and Ξ²-catenin and their correlation with clinicopathological parameters in non-small cell lung cancer: p130cas over-expression predicts poor prognosis

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    p130cas (p130 Crk-associated substrate) is a scaffolding protein and plays an important role in regulating focal adhesion and driving cell migration. Also, the destruction of E-cadherin/Ξ²-catenin adhesive complex is one of the changes that characterizes the invasive phenotype of tumors. The aim of this study is to evaluate the role of p130cas, E-cadherin, and Ξ²-catenin expression in patients with non-small cell lung cancer (NSCLC). We examined the expression of p130cas, E-cadherin, and Ξ²-catenin in 105 lung cancer tissues and paired adjacent normal lung tissues using immunohistochemistry. The overexpression of p130cas was observed in 61.9% (65/105) of lung cancer samples. The overexpression of p130cas was correlated with abnormal expression of E-cadherin and Ξ²-catenin (P=0.002 and P=0.006, respectively). Chi-square test showed that the overexpression of p130cas correlated positively with lymph node metastasis and high TNM stage. The Log-Rank test revealed that the mean survival time of patients with p130cas overexpression (36.31 Β± 5.66 months) was markedly shorter than those with p130cas normal expression (60.57 Β± 6.95 months). Multivariable analysis indicated p130cas overexpression (P<0.001) as an independent significant prognostic factor for NSCLC patients’ survival. These results indicate that p130cas may impact a variety of clinicopathological features of NSCLC and may y influence the prognosis of lung cancer patients
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