193 research outputs found

    Unusual Compression Behavior of Columbite TiO2 via First-Principles Calculations

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    The physical mechanisms behind the reduction of the bulk modulus of a high-pressure cubic TiO2 phase are confirmed by first-principles calculations. An unusual and abrupt change occurs in the dependence of energy on pressure at 43 GPa, indicating a pressure-induced phase transition from columbite TiO2 to a newly-identified modified fluorite TiO2 with a Pca21 symmetry. Oxygen atom displacement in Pca21 TiO2 unexpectedly reduces the bulk modulus by 34% relative to fluorite TiO2. This discovering provides a direct evidence for understanding the compressive properties of such groups of homologous materialsComment: [email protected] or [email protected]

    Serum high-sensitivity C-reactive protein levels in comorbid patients with type-2 diabetes mellitus and periodontal disease

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    Purpose: To investigate the relationship between serum levels of high-sensitivity C-reactive protein (hs-CRP) and the severity of periodontal disease in diabetics with periodontitis.Methods: Ninety patients were recruited for this study. They were divided into three groups, namely, group 1 (30 patients with type 2 diabetes mellitus (T2DM) and periodontal disease), group II (30 patients with T2DM only) and control (30 healthy individuals). Serum levels of hs-CRP and glycosylated hemoglobin (HbAc) were determined. Moreover, blood glucose (BG) and insulin (FNS) levels were determined in the fasted state, and their values used to compute insulin resistance index (Homa-IR).Results: Serum levels of FNS, FPG, HbAc and Homa-IR in group I patients were significantly higher (p < 0.05) than those of control group. While the levels of BG and Homa-IR in the serum of patients in groups I and II were significantly higher (p < 0.05) than those of control, marked reductions were seen in their values in group II, relative to group I. The serum levels of hs-CRP in group I and II were significantly increased (p < 0.05) relative to control, but were lower in group II than in group I (p < 0.05). Homa-IR was positively correlated with serum hs-CRP, FNS, BG, HbAc, and Homa-IR in groups I and II. Results from multiple regression analysis revealed significant effects of hs-CRP and HbAc on Homa-IR.Conclusion: Serum levels of hs-CRP in patients with T2DM and periodontitis are closely related to disease severity, insulin resistance and blood glucose level.Keywords: Type-2 diabetes mellitus, Periodontal disease, High-sensitivity C-reactive protein, Blood glucose, Insulin resistance, Correlatio

    Ab initio study of the formation of transparent carbon under pressure

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    A body-centered tetragonal carbon (bct-Carbon) allotrope has been predicted to be a transparent carbon polymorph obtained under pressure. The structural transition pathways from graphite to diamond, M-Carbon, and bct-Carbon are simulated and the lowest activation barrier is found for the graphite-bct transition. Furthermore, bct-Carbon has higher shear strength than diamond due to its perpendicular graphene-like structure. Our results provide a possible explanation for the formation of a transparent carbon allotrope via the cold compression of graphite. We also verify that this allotrope is hard enough to crack diamond.Comment: [email protected] or [email protected]

    Genetic variants of DNA repair genes predict the survival of patients with esophageal squamous cell cancer receiving platinum-based adjuvant chemotherapy

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    Additional file 2: Table S2. Stratified univariate analysis of DFS and OS between LG* and HG* in Chinese ESCC patients

    Efficient spectral broadening and few-cycle pulse generation with multiple thin water films

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    High-energy, few-cycle laser pulses are essential for numerous applications in the fields of ultrafast optics and strong-field physics, due to their ultrafast temporal resolution and high peak intensity. In this work, different from the traditional hollow-core fibers and multiple thin solid plates, we represent the first demonstration of the octave-spanning supercontinuum broadening by utilizing multiple ultrathin liquid films (MTLFs) as the nonlinear media. The continuum covers a range from 380 to 1050 nm, corresponding to a Fourier transform limit pulse width of 2.5 fs, when 35 fs Ti:sapphire laser pulse is applied on the MTLFs. The output pulses are compressed to 3.9 fs by employing chirped mirrors. Furthermore, a continuous high-order harmonic spectrum up to the 33rd order is realized by subjecting the compressed laser pulses to interact with Kr gas. The utilization of flowing water films eliminates permanent optical damage and enables wider and stronger spectrum broadening. Therefore, this MTLFs scheme provides new solutions for the generation of highly efficient femtosecond supercontinuum and nonlinear pulse compression, with potential applications in the fields of strong-field physics and attosecond science.Comment: 9 pages, 5 figure
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