193 research outputs found
Unusual Compression Behavior of Columbite TiO2 via First-Principles Calculations
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
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
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]
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Crif1 Promotes Osteoporosis in Mice after Radiation
Abstract Radiation induces rapid bone loss and enhances bone resorption and RANKL expression. RANKL provides the crucial signal to induce osteoclast differentiation and plays an important role in bone resorption. However, the mechanisms of radiation-induced osteoporosis are not fully understood. Here, we show that Crif1 expression increases in bone marrow cells after radiation. Conditional Crif1 deletion in bone marrow cells causes decreases in RANKL expression and the RANKL/OPG ratio, and relieves bone loss after radiation in mice. We further demonstrated in vitro that Crif1 promotes RANKL secretion via the cAMP/PKA pathway. Moreover, protein-protein docking screening identified five compounds as Crif1 inhibitors; these compounds dramatically suppressed RANKL secretion and CREB phosphorylation when cells were exposed to forskolin. This study enriches current knowledge of the pathogenesis of osteoporosis and provides insights into potential therapeutic strategies for osteoporosis treatment
Genetic variants of DNA repair genes predict the survival of patients with esophageal squamous cell cancer receiving platinum-based adjuvant chemotherapy
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
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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