Lei Li

Lanzhou University, Kao-lan-hsien, Gansu Sheng, China

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Publications (69)134.11 Total impact

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    ABSTRACT: The electronic and magnetic properties of RbS and KS in CsCl structure have been investigated by using the full-potential local-orbital minimum-basis method. Calculating the relation between the total energies and lattice parameters for RbS and KS, we find out that the equilibrium lattice parameters are 4.02 Å and 3.84 Å for RbS and KS, respectively. According to our calculations in generalized gradient approximation approximation, both RbS and KS are half-metallic ferromagnets with the magnetic moments of 1 μB per formula unit, and band gap of 4.287 eV for RbS and 4.395 eV for KS. We also have studied the electronic and magnetic properties of (1 1 1) surfaces of RbS and KS, and have found out that the half-metallicity of their bulk is preserved in all of those surfaces. Finally, through the calculations of formation energy of RbS and KS, it is found that their thin films are stable in the equilibrium conditions, and the Rb-terminated (1 1 1) slab of RbS and the K-terminated (1 1 1) slab of KS are more stable than their S-terminated (1 1 1) slabs. All of the above properties lead the compounds of RbS and KS in CsCl structure to be promising candidates for spintronic applications.
    Materials Research Bulletin 08/2015; 68. DOI:10.1016/j.materresbull.2015.03.048 · 1.97 Impact Factor
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    ABSTRACT: We investigate the electronic structure and magnetic properties of four quaternary Heusler alloys ZrMnVZ and ZrCoFeZ (Z = Si, Ge) by using first-principle calculations. It is shown that ZrMnVSi, ZrMnVGe and ZrCoFeSi are half-metallic ferromagnets with considerable half-metallic gaps of 0.14, 0.18 and 0.22 eV, respectively. ZrCoFeGe is nearly half-metallic with a spin polarization of 98.99% at equilibrium lattice constant. Meanwhile, the changes of its properties under pressure are investigated.
    Computational Materials Science 06/2015; 103. DOI:10.1016/j.commatsci.2015.03.010 · 1.88 Impact Factor
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    ABSTRACT: We investigate the electronic structures and magnetic properties of RbSe and CsTe compounds in CsCl, RS and ZB structures by using first-principles calculation. It is shown that these two compounds exhibit half-metallic ferromagnetism with an integer magnetic moment of 1.00 $\mu_B$ per formula in all the three structures. Total energy calculations indicate the CsCl phase is more stable than the other two phases. We investigate these two compounds with CsCl structure in detail. The ferromagnetism results mainly from the spin-polarization of p states of anion Se (Te) for the two compounds. The half-metallicities of RbSe and CsTe compounds can be preserved up to 2.5\% and 0.8\% compression of lattice constants with respect to their equilibrium lattices, respectively.
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    ABSTRACT: PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Our previous study has shown that PNAS-4 induces S phase arrest and apoptosis when overexpressed in A549 lung cancer cells. However, the underlying action mechanism remains far from clear. In this work, we found that PNAS-4 expression in lung tumor tissues is significantly lower than that in adjacent lung tissues and its expression is significantly increased in A549 cells after exposure to cisplatin, methyl methane sulfonate (MMS) and mitomycin (MMC), and that its overexpression induces S-phase arrest and apoptosis in A549 (p53 WT), NCI-H460 (p53 WT), H526 (p53 mutation) and Calu-1 (p53 -/-) lung cancer cells, leading to proliferation inhibition irrespective of their p53 status. The S phase arrest is associated with upregulation of p21waf1/Cip1 and inhibition of the Cdc25A-CDK2-Cyclin E/A pathway. Upregulation of p21waf1/Cip1 is p53-independent and correlates with activation of ERK. We further showed that the intra-S-phase checkpoint, which occurs via DNA-PK-mediated activation of Chk1 and Chk2, is involved in the S-phase arrest and apoptosis. Gene silencing of Chk1/2 rescues, whereas that of ATM or ATR does not affect, S-phase arrest and apoptosis. Furthermore, hPNAS-4 induces DNA breaks in comet assays and γ-H2AX staining. Intriguingly, caspase-dependent cleavage of Chk1 has an additional role in enhancing apoptosis. Taken together, our findings suggest a novel mechanism by which elevated PNAS-4 first causes DNA-PK-mediated Chk1/2 activation, then results in inhibition of Cdc25A-Cdk2-Cyclin E/A pathway, ultimately causing S-phase arrest and apoptosis in lung cancer cells. Copyright © 2015, The American Society for Biochemistry and Molecular Biology.
    Journal of Biological Chemistry 04/2015; DOI:10.1074/jbc.M115.658419 · 4.60 Impact Factor
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    ABSTRACT: The electronic and magnetic properties of bulk and (1 1 1) surfaces for MP (M=K ans Rb) in rocksalt structure have been investigated by employing first-principle calculations. The results reveal that the compounds are half-metallic ferromagnets at the equilibrium lattice constants with large half-metallic band gaps of 0.46 and 0.74 eV. The (111) surfaces of KP and RbP keep their bulk half-metallic property. We study the stabilities of the bulk compounds and their (1 1 1) surfaces as well.
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    Journal of Magnetism and Magnetic Materials 04/2015; 379:288-293. DOI:10.1016/j.jmmm.2014.12.025 · 2.00 Impact Factor
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    ABSTRACT: Abstract We report a novel β-globin gene promoter mutation in a Chinese family identified using fluorescence resolution melting curve analysis and gene sequencing. The proband, who showed the phenotype of β-thalassemia intermedia (β-TI), was found to be a compound heterozygote for the novel mutation -25 (G>T) (HBB: c.-75G>T) and a codon 17 (HBB: c.52A>T) mutation. Moreover, conservation analysis using phyloP and phastCons indicated that the mutated base in the proband was conserved. This novel point mutation on the β-globin gene is in close proximity to the conserved ATAA sequence located at position -25 relative to the mRNA Cap site. We performed a further comparative analysis of the clinical phenotypes and hematological parameters in this pedigree and found that the father was a carrier of the novel point mutation and showed low levels of hemoglobin (Hb), mean corpuscular volume (MCV) and mean corpuscular Hb (MCH). Thus, the available evidence suggests that this novel mutation, -25, results in β(+)-thalassemia (β(+)-thal).
    Hemoglobin 02/2015; DOI:10.3109/03630269.2014.1002844 · 0.96 Impact Factor
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    ABSTRACT: In this letter, we investigate the magnetic properties, electronic structures, Slater-Pauling behaviours of some quanternary Heusler alloys with 4d and 3d transition metal elements. The energy levels of the minority-spin electronic band structures for all our calculated alloys are discussed. We have summaried 21 quanternary Heusler alloys. Our calculations indicate that the half metals ZrCoCrSi, ZrCoCrIn, ZrCoFeSi, ZrFeVAl, ZrFeVGa and NbFeCrAl have large spin-flip gaps.
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    ABSTRACT: We investigate the electronic structure and magnetic properties of four quaternary Heusler alloys ZrMnVZ and ZrCoFeZ (Z=Si, Ge) by using first-principle calculations. It is shown that ZrMnVSi, ZrMnVGe and ZrCoFeSi are half-metallic ferromagnets with considerable half-metallic gaps of 0.14, 0.18 and 0.22 eV, respectively. ZrCoFeGe is a nearly half-metallic, the changes of properties for this alloy under pressure is investigated, the spin polarization of this alloy is 98.99\% at equilibrium lattice constant.
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    ABSTRACT: To compare the effects of metformin with insulin on maternal and neonatal outcomes in gestational diabetes mellitus (GDM). A literature search in PUBMED, EMBASE, Science Direct, Springer link, and Cochrane library was conducted using the following search terms: "Gestational Diabetes" or "GDM", and "insulin" and "metformin". Quality assessment of included studies was determined with Quality Assessment of Diagnostic Accuracy Studies. Review Manger 5.2 was used to analyze mean difference (MD)/risk ratio (RR) and 95 % confidence interval (CI) in random-effects model or fixed-effects model depending on the level of heterogeneity. A total of 11 studies were identified. There was no significant difference of the effect on maternal outcomes between the two treatments in glycohemoglobin A1c levels (P = 0.37), fasting blood glucose (P = 0.66), and the incidence of preeclampsia (P = 0.26); whereas, significantly reduced results were found in the metformin group in pregnancy-induced hypertension (PIH) rate (RR = 0.53, 95 % CI 0.31-0.90, P = 0.02), average weight gains after enrollment (MD = -1.28, 95 % CI -1.54 to -1.01, P < 0.0001), and average gestational ages at delivery (MD = 0.94, 95 % CI -0.21 to -0.01, P = 0.03). Regarding neonatal outcomes, when compared with insulin group, metformin presented significantly lower average birth weights (MD = -44.35, 95 % CI -85.79 to -2.90, P = 0.04), incidence of hypoglycemia (RR = 0.69, 95 % CI 0.55-0.87, P = 0.001) and neonatal intensive care unit (NICU) (RR = 0.82, 95 % CI 0.67-0.99, P = 0.04). Metformin can significantly reduce several adverse maternal and neonatal outcomes including PIH rate, incidence of hypoglycemia and NICU, thus it may be an effective and safe alternative or additional treatment to insulin for GDM women.
    Archives of Gynecology and Obstetrics 12/2014; 292(1). DOI:10.1007/s00404-014-3566-0 · 1.28 Impact Factor
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    ABSTRACT: A new imidazo[1,5-a]pyridine-containing pyrrolyl ligand HL (HL = 3-(1H-pyrrol-2-yl)imidazo[1,5-a]pyridine) has been synthesized and employed to the organometallic chemistry of titanium. The syntheses, structures, catalytic properties and antitumor activity of three titanium complexes supported by HL are reported. Reactions of Ti(NMe2)4 and Ti(NEt2)4, respectively, with 2 equivalents of HL, lead to the production of titanium bisamido complexes TiL2(NMe2)2 (1) and TiL2(NEt2)2 (2). Treatment of Ti(OiPr)4 with 2 equivalents of HL results in the formation of TiL2(OiPr)2 (3). All complexes have been characterized by elemental analyses and NMR studies. The solid-state structures of 2 and 3 have been further established by single X-ray crystallography. The titanium bisamido complexes 1 and 2 are shown to be good pre-catalysts for the hydroamination of alkynes. Complex 1 was found to be active catalyst for the ring-opening polymerization of ε-caprolactone. The cytotoxicity activities of 3 towards the tumor cells HCT-116, PC3 and MCF-7 were measured. Complex 3 exhibited good antitumor properties.
    RSC Advances 12/2014; 5(14). DOI:10.1039/C4RA14692A · 3.71 Impact Factor
  • Zhonghua bing li xue za zhi Chinese journal of pathology 12/2014; 43(12):845-6.
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    ABSTRACT: Employing $ab$ $intito$ electronic structure calculations, we have investigated electronic and magnetic properties of the Zr-based quanternary Heusler alloys: VZrCoIn, VZrFeGe, FeZrCoP, CrZrCoBe and CrZrFeZ (Z=In and Ga). Our $ab$ $intito$ calculation results show that all the alloys are (or nearly) spin-gapless semiconductors. All the alloys have large band gaps, indicating the stability of them at room temperature. The Slater-Pauling behaviours of these alloys are discussed as well. The values of Curie temperature of all the alloys are estimated. And it is found that the values of the Curie temperature for all our calculated quanternary Heusler alloys are higher than that of room temperature.
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    ABSTRACT: Human plasminogen kringle 5 (K5) is known to display its potent anti-angiogenesis effect through inducing endothelial cell (EC) apoptosis, and the voltage-dependent anion channel 1 (VDAC1) has been identified as a receptor of K5. However, the exact role and underlying mechanisms of VDAC1 in K5-induced EC apoptosis remain elusive. In the current study, we showed that K5 increased the protein level of VDAC1, which initiated the mitochondrial apoptosis pathway of ECs. Our findings also showed that K5 inhibited the ubiquitin-dependent degradation of VDAC1 by promoting the phosphorylation of VDAC1, possibly at Ser12 and Thr107. The phosphorylated VDAC1 was attenuated by AKT agonist, GSK3β inhibitor and siRNA,suggesting that K5 increased VDAC1 phosphorylation via the AKT-GSK3β pathway. Furthermore, K5 promoted cell surface translocation of VDAC1, and binding between K5 and VDAC1 was observed on the plasma membrane. HKI protein blocked the impact of K5 on the AKT-GSK3β pathway by competitively inhibiting the interaction of K5 and cell surface VDAC1. Moreover, K5-induced EC apoptosis was suppressed by VDAC1 antibody. These data show for the first time that K5-induced EC apoptosis is mediated by the positive feedback loop of "VDAC1-AKT-GSK3β-VDAC1", which may provide new perspectives on the mechanisms of K5-induced apoptosis.
    Journal of Biological Chemistry 10/2014; DOI:10.1074/jbc.M114.567792 · 4.60 Impact Factor
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    ABSTRACT: Pigment epithelium-derived factor (PEDF) plays an important role in the tumor growth and metastasis inhibition. It has been reported that PEDF expression is significantly reduced in breast cancer, and associated with disease progression and poor patient outcome. However, the exact mechanism of PEDF on breast cancer metastasis including liver and lung metastasis remains unclear. The present study aims to reveal the impact of PEDF on breast cancer. The orthotopic tumor mice model inoculated by MDA-MB-231 cells stably expressing PEDF or control cells was used to assess liver and lung metastasis of breast cancer. In vitro, migration and invasion experiments were used to detect the metastatic abilities of MDA-MB-231 and SKBR3 breast cancer cells with or without overexpression of PEDF. The metastatic-related molecules including EMT makers, fibronectin, and p-AKT and p-ERK were detected by qRT-PCR, Western blot, and Fluorescent immunocytochemistry. PEDF significantly inhibited breast cancer growth and metastasis in vivo and in vitro. Mechanically, PEDF inhibited breast cancer cell migration and invasion by down-regulating fibronectin and subsequent MMP2/MMP9 reduction via p-ERK and p-AKT signaling pathways. However, PEDF had no effect on EMT conversion in the breast cancer cells which was usually involved in cancer metastasis. Furthermore, the study showed that laminin receptor mediated the down-regulation of fibronectin by PEDF. These results reported for the first time that PEDF inhibited breast cancer metastasis by down-regulating fibronectin via laminin receptor/AKT/ERK pathway. Our findings demonstrated PEDF as a dual effector in limiting breast cancer growth and metastasis and highlighted a new avenue to block breast cancer progression.
    Breast Cancer Research and Treatment 10/2014; 148(1). DOI:10.1007/s10549-014-3154-9 · 4.20 Impact Factor
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    ABSTRACT: Pigment epithelium-derived factor (PEDF), a potent anti-angiogenesis agent, has recently attracted attention for targeting tumor cells in several types of tumors. However, less is known about the apoptosis-inducing effect of PEDF on human lung cancer cells and the underlying molecular events. Here, we report that PEDF has a growth-suppressive and pro-apoptotic effect on lung cancer xenografts. Accordingly, in vitro, PEDF apparently induced apoptosis in A549 and Calu-3 cells predominantly via the Fas-L/Fas death signaling pathway. Interestingly, A549 and Calu-3 cells are insensitive to the Fas-L/Fas apoptosis pathway because of the low level of cell surface Fas. Our results revealed that, in addition to the enhancement of Fas-L expression, PEDF increased the sensitivity of A549 and Calu-3 cells to Fas-L-mediated apoptosis by triggering the translocation of Fas protein to plasma membrane in a p53- and FAP-1-dependent manner. Similarly, the up-regulation of Fas-L by PEDF was also mediated by p53. Furthermore, PPARγ was determined to be the upstream regulator of p53. Together, these findings uncover a novel mechanism of tumor cell apoptosis induced by PEDF and provide a potential therapeutic strategy for those tumors that are insensitive to Fas-L/Fas-dependent apoptosis due to the low level of cell surface Fas.
    Journal of Biological Chemistry 09/2014; 289(44). DOI:10.1074/jbc.M114.590000 · 4.60 Impact Factor
  • Zhonghua bing li xue za zhi Chinese journal of pathology 09/2014; 43(9):627-8.
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    ABSTRACT: Gastric cancer and breast cancer have a clear tendency toward metastasis and invasion to the microenvironment predominantly composed of adipocytes. Oleic acid is an abundant monounsaturated fatty acid that releases from adipocytes and impinges on different energy metabolism responses. The effect and underlying mechanisms of oleic acid on highly metastatic cancer cells are not completely understood. We reported that AMP-activated protein kinase (AMPK) was obviously activated in highly aggressive carcinoma cell lines treated by oleic acid, including gastric carcinoma HGC-27 and breast carcinoma MDA-MB-231 cell lines. AMPK enhanced the rates of fatty acid oxidation and ATP production and thus significantly promoted cancer growth and migration under serum deprivation. Inactivation of AMPK attenuated these activities of oleic acid. Oleic acid inhibited cancer cell growth and survival in low metastatic carcinoma cells, such as gastric carcinoma SGC7901 and breast carcinoma MCF-7 cell lines. Pharmacological activation of AMPK rescued the cell viability by maintained ATP levels by increasing fatty acid β-oxidation. These results indicate that highly metastatic carcinoma cells could consume oleic acid to maintain malignancy in an AMPK-dependent manner. Our findings demonstrate the important contribution of fatty acid oxidation to cancer cell function.
    PLoS ONE 05/2014; 9(5):e97330. DOI:10.1371/journal.pone.0097330 · 3.53 Impact Factor
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    ABSTRACT: Mucinous minimal deviation adenocarcinoma (MDA) is a rare highly differentiated tumor of uterine cervix, of which the confusing histopathology resembling some benign lesions usually makes difficulty for pathologic diagnosis. The expression of forkhead box protein P1 (FOXP1) is found in some kinds of human tumors and is considered to be associated with the progression of the tumors. The purpose of this study is to detect the FOXP1 expression in MDA and evaluate its possible role in the diagnosis of MDA. Twenty-two MDA cases and 20 control cases consisting of 10 cases of lobular endocervical glandular hyperplasia and 10 cases of normal endocervical tissue were included in this study. All available clinical data were collected and immunostaining for FOXP1, carcinoembryonic antigen (CEA), human milk fat globule antigen 1 (HMFG1), estrogen receptor, and progesterone receptor were performed on these cases. The nuclear/cytoplasmic expression of FOXP1 was found in 18 of 22 MDA cases while in 1 of 20 control cases, which showed statistical significance (P = .000). The cytoplasmic CEA expression was found in 14 of 22 MDA cases and 2 of 20 control cases (P = .000), whereas cytoplasmic HMFG1 expression was found in 10 of 22 MDA cases and 4 of 20 control cases (P = .081). No statistical difference was found between FOXP1 and CEA expression (P = .083) or between FOXP1 and HMFG1 expression (P = .375) in MDA. Neither estrogen receptor nor PR expression was found in MDA. The significant expression of FOXP1 in MDA may be helpful to some extent in the pathologic diagnosis of cervical MDA. A widened observation range and further researches are needed to elucidate the potential mechanism.
    Annals of Diagnostic Pathology 05/2014; DOI:10.1016/j.anndiagpath.2014.04.003 · 1.11 Impact Factor
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    ABSTRACT: Using first-principles calculations within generalized gradient approximation, the electronic and magnetic properties of zinc-blende (Si, AE)C and (Ga, AE)N (AE = Mg, Ca, Sr and Ba) superlattice are investigated. We focus on two simple layer-by-layer delta doping structures with the alkaline earth substituting along the (1 0 0) planes and (0 0 1). Ga0.5Ca0.5N, Ga0.5Sr0.5N, Ga0.5Ba0.5N and Si0.5Ca0.5C are found to be half-metallic ferromagnets according to our calculations. Meanwhile, GaN substrates with Ca- or Sr- show robust half-metallicity property. The electronic structures revealed that the zinc-blende Si0.5Sr0.5C have a tendency to exhibit half-metallicity on the isotropic strain; however, Ga0.5Ca0.5N and Ga0.5Sr0.5N superlattices became half-metal when the biaxial strains were imposed. Furthermore, phase transitions from AFM to FM states are also considered for the strain of Ba-alloyed GaN and Mg-alloyed SiC. This study provides a general picture of the magnetic and half-metallic properties of alkaline earth-alloyed SiC and GaN thin films, which is helpful in exploring half-metallic ferromagnets in future.
    Journal of Superconductivity and Novel Magnetism 04/2014; 27(4). DOI:10.1007/s10948-013-2372-4 · 0.93 Impact Factor

Publication Stats

121 Citations
134.11 Total Impact Points

Institutions

  • 2014–2015
    • Lanzhou University
      • School of Physical Science and Technology
      Kao-lan-hsien, Gansu Sheng, China
    • Guangzhou Medical University
      Shengcheng, Guangdong, China
  • 2011–2014
    • Soochow University (PRC)
      • Key Laboratory of Organic Synthesis of Jiangsu Province
      Wu-hsien, Jiangsu Sheng, China
  • 2010–2014
    • Sun Yat-Sen University
      • Department of Biochemistry
      Shengcheng, Guangdong, China
    • Guangzhou Center for Disease Control
      Shengcheng, Guangdong, China
  • 2005–2014
    • Sichuan University
      • • Department of Pathology
      • • Department of Obstetrics and Gynecology
      Hua-yang, Sichuan, China
  • 2013
    • Zhengzhou University
      Cheng, Henan Sheng, China
  • 2012–2013
    • Suzhou University
      • College of Chemistry and Chemical Engineering
      Suchow, Anhui Sheng, China