Enzymatic degradation of demineralized collagen matrix seriously impairs durable resin-dentin bonding. In this study, we evaluated the effect of nordihydroguaiaretic acid （NDGA）-modified etchant on the resistance to...Enzymatic degradation of demineralized collagen matrix seriously impairs durable resin-dentin bonding. In this study, we evaluated the effect of nordihydroguaiaretic acid （NDGA）-modified etchant on the resistance to enzymatic degradation and mechanical properties of demineralized collagen matrix. Dentin beams were randomly demineralized by following solutions： 1 ） 10% phosphoric acid （PhA） solution, 2） 10% dimethyl sulfoxide （DMSO）-PhA solution, 3） NDGA-modified etchant, and 4） proanthocyanidins （PA）-modified etchant. The demineralized dentin collagen was then digested by type l collagenase solution. The collagenase degradation resistance was evaluated by measuring loss of dry mass, hydroxyproline release, and elastic modulus change. The degradation rate and hydroxyproline release of dentin collagen treated with NDGA-modified etchant were significantly lower than those in the other groups （P〈 0.001）. The elastic modulus of dentin beams treated with NDGA-modified etchant did not increase significantly. However, after 48 h of collagenase degradation, the loss of elastic modulus of dentin beams treated with NDGA-modified etchant was significantly lower than that of the control group （P〈 0.001）. The NDGA-modified etchant could improve the resistance to enzymatic degradation of type l collagenase degradation, and the stability of the mechanical properties of dentin collagen. This proof-of-concept study validates the etch-and-crosslink technique that improves durability of dentin bonding through simultaneous dentin etching and collagen crosslinking.展开更多
We build holographic p-wave conductor(insulator)/superconductor models via the numerical method with a new form of Weyl coupling in five-dimensional Lifshitz gravity,and then investigate how the Weyl coupling paramete...We build holographic p-wave conductor(insulator)/superconductor models via the numerical method with a new form of Weyl coupling in five-dimensional Lifshitz gravity,and then investigate how the Weyl coupling parameterγand the Lifshitz scaling parameter z affect the superconductor models.In the conductor/superconductor model,an increase in the Weyl correction(Lifshitz scaling)enhances(inhibits)the superconductor phase transition.Meanwhile,both the Weyl correction(when the Lifshitz parameter is large enough and fixed)and the Lifshitz scaling suppress the growth of the real part of the conductivity.The Weyl correction used here(CB^(2))shows weaker effects on the critical value than the previous Weyl correction(CF^(2)).In the insulator/superconductor model,larger vaules of the Weyl parameter hinder the formation of condensate.However,in increase in the Lifshitz scaling enhances the appearance of condensate.In addition,the calculation suggests that a competitive relation may exist between the Weyl correction and the Lifshitz scaling.展开更多
Based on the dynamics of single scalar field slow-roll inflation and the theory of reheating,we investigate the generalized natural inflationary(GNI)model.We introduce constraints on the scalar spectral index ns and t...Based on the dynamics of single scalar field slow-roll inflation and the theory of reheating,we investigate the generalized natural inflationary(GNI)model.We introduce constraints on the scalar spectral index ns and the tensor-to scalar ratio r for theΛCDM+r model,according to the latest data from Planck 2018 TT,TE,EE+low E+lensing(P18)and BICEP2/Keck 2015 season(BK15),i.e.,with ns=0.9659±0.0044 at 68%confidence level(CL),and r<0.0623 at 95%CL.We find that the GNI model is favored by P18 and BK15 in the ranges log10(f/Mp)=0.62^+0.17−0.18 and m=0.35^+0.13−0.23 at 68%CL.In addition,the corresponding predictions of generalized and two-phase reheating are discussed.It follows that the parameter m has significant effect on the model behavior.展开更多
基金supported by the Projects of the National Natural Science Foundation of China(No. 81571815 (Y. Liu),No. 81401525 (S.Q. Gong))the Beijing Municipal Natural Science Foundation(No. 7152156 (Y. Liu))Beijing New-star Plan of Science and Technology(No. Z171100001117018 (Y. Liu))
文摘Enzymatic degradation of demineralized collagen matrix seriously impairs durable resin-dentin bonding. In this study, we evaluated the effect of nordihydroguaiaretic acid （NDGA）-modified etchant on the resistance to enzymatic degradation and mechanical properties of demineralized collagen matrix. Dentin beams were randomly demineralized by following solutions： 1 ） 10% phosphoric acid （PhA） solution, 2） 10% dimethyl sulfoxide （DMSO）-PhA solution, 3） NDGA-modified etchant, and 4） proanthocyanidins （PA）-modified etchant. The demineralized dentin collagen was then digested by type l collagenase solution. The collagenase degradation resistance was evaluated by measuring loss of dry mass, hydroxyproline release, and elastic modulus change. The degradation rate and hydroxyproline release of dentin collagen treated with NDGA-modified etchant were significantly lower than those in the other groups （P〈 0.001）. The elastic modulus of dentin beams treated with NDGA-modified etchant did not increase significantly. However, after 48 h of collagenase degradation, the loss of elastic modulus of dentin beams treated with NDGA-modified etchant was significantly lower than that of the control group （P〈 0.001）. The NDGA-modified etchant could improve the resistance to enzymatic degradation of type l collagenase degradation, and the stability of the mechanical properties of dentin collagen. This proof-of-concept study validates the etch-and-crosslink technique that improves durability of dentin bonding through simultaneous dentin etching and collagen crosslinking.
基金supported in part by NSFC(Grant Nos.11865012,12075109,12075143 and 11747615)the Foundation of Scientific Innovative Research Team of Education Department of Guizhou Province(201329)。
文摘We build holographic p-wave conductor(insulator)/superconductor models via the numerical method with a new form of Weyl coupling in five-dimensional Lifshitz gravity,and then investigate how the Weyl coupling parameterγand the Lifshitz scaling parameter z affect the superconductor models.In the conductor/superconductor model,an increase in the Weyl correction(Lifshitz scaling)enhances(inhibits)the superconductor phase transition.Meanwhile,both the Weyl correction(when the Lifshitz parameter is large enough and fixed)and the Lifshitz scaling suppress the growth of the real part of the conductivity.The Weyl correction used here(CB^(2))shows weaker effects on the critical value than the previous Weyl correction(CF^(2)).In the insulator/superconductor model,larger vaules of the Weyl parameter hinder the formation of condensate.However,in increase in the Lifshitz scaling enhances the appearance of condensate.In addition,the calculation suggests that a competitive relation may exist between the Weyl correction and the Lifshitz scaling.
基金Supported by the National Natural Science Foundation of China(11575075,11705079,11865012)。
文摘Based on the dynamics of single scalar field slow-roll inflation and the theory of reheating,we investigate the generalized natural inflationary(GNI)model.We introduce constraints on the scalar spectral index ns and the tensor-to scalar ratio r for theΛCDM+r model,according to the latest data from Planck 2018 TT,TE,EE+low E+lensing(P18)and BICEP2/Keck 2015 season(BK15),i.e.,with ns=0.9659±0.0044 at 68%confidence level(CL),and r<0.0623 at 95%CL.We find that the GNI model is favored by P18 and BK15 in the ranges log10(f/Mp)=0.62^+0.17−0.18 and m=0.35^+0.13−0.23 at 68%CL.In addition,the corresponding predictions of generalized and two-phase reheating are discussed.It follows that the parameter m has significant effect on the model behavior.
