In the present paper an analytical potential form is used for overlap repulsive energy, derived by Harrison from quantum mechanical considerations, along with the composite effect of three-body forces and intersublattice displacement. The short-range overlap parameters in Harrison's potential form have direct correlation with the valence state energies for outermost electrons. The potential model is applied to calculate the third and fourth order elastic constants, first and second pressure derivatives of second order elastic constants, Grüneisen parameter and its volume dependence, Anderson parameter, and thermal expansion coefficient for three non-centrosymmetric crystals, viz. CaF2, SrF2 and BaF2. The calculated values of various physical quantities are found to be in good agreement with experimental data.The authors are grateful to Dr. Mansour Khalef, the Head of Physics Department, TNRC, Tajura (Tripoli) for the facilities and encouragements. 相似文献
The complex anatomy of teeth limits the accessibility and efficacy of regenerative treatments. Therefore, the application of well-known inducers as injectable hydrogels for the regeneration of the dentin-pulp complex is considered a promising approach. In this regard, this study aimed to develop an injectable hydrogel containing mineral trioxide aggregate (MTA). The injectable chitosan/oxidized-nanocrystalline cellulose/MTA (CS/OCNC/MTA) hydrogels were prepared, and the physicochemical properties of these hydrogels were evaluated by TGA, FTIR, Rheological analysis, and SEM. Moreover, the effect of MTA on the swelling and degradability of scaffolds was assessed. The proliferative effects of synthesized hydrogels were also determined on human dental pulp stem cells (hDPSCs) by MTT assay. For induction of differentiation and biomineralization in these cells, the alkaline phosphatase activity and Alizarin Red S staining tests were performed in the presence of fabricated scaffolds. The proliferation of hDPSCs was significantly increased in the presence of these hydrogels. Moreover, the addition of MTA to hydrogel structure dramatically improved the differentiation of hDPSCs. These results suggested that this novel injectable hydrogel provides appropriate physiochemical properties and can be considered a promising scaffold for regenerative endodontic procedures.
An efficient method for the oxidative coupling of thiols to their corresponding disulfides by new reagents poly(N‐bromobenzene‐1,3‐disulfonylamide) PBBS , N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonylamide TBBDA and DABCO‐bromine complex is described. The reaction was applicable to a variety of thiols with high chemoselectivity. 相似文献
Tribromoisocyanuric acid (TBCA) and Oxone®‐MX systems were used as effective oxidizing agents for the oxidation of thiols to their corresponding disulfides under mild conditions at room temperature with good to excellent yields. 相似文献
Aliphatic and aromatic 1,3‐dithiane are oxidized to the corresponding carbonyl compounds in good yields under mild conditions by N,N′‐diiodo‐N,N′‐1,2‐ethanediyl‐bis(p‐toluenesulphonamide) [NIBTS] and silver nitrate. 相似文献
Poly [N‐bromo‐benzene‐1,3‐disulfonylamide] [ PBBS ] is a novel and efficient reagent for the conversion of oximes and semicarbazones under solid state to their corresponding carbonyl compounds in high yields. 相似文献
The crystal structure of 1-Methyl-3-([2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidene]methyl)urea (C9H12N2O5) has been determined by single crystal X-ray diffraction analysis. The crystals are monoclinic, a = 5.3179(2), b = 18.6394(6), c =10.8124(3) Å, β = 100.015(2)°, Z = 4, sp. gr. P21/c, R = 0.0381 for 2537 reflections with I > 2σ(I). Except for C(CH3)2 group, the molecule is planar. The structure is stabilized by inter- and intramolecular N-H...O hydrogen bonds and weak C-H...O interactions. 相似文献
LDH/Tris/Pd (CaAl‐layered double hydroxide/tris (hydroxymethyl)aminomethane/palladium) was synthesized and appraised for its catalytic activity towards the degradation of two selected azo dyes. The decolorization of azo dyes, acid red 18 (AR 18) and reactive yellow 15 (RY 15), requires considerably small amounts of synthesized catalyst. Kinetic studies show that the catalytic decolorization of these azo dyes follows the first order kinetic model. The reported method is simple and applicable; in addition, the stable catalyst can efficiently decolorize model azo dyes with good recyclability. Therefore, LDH/Tris/Pd can be accepted as the possible component for the utilization in wastewater treatment. 相似文献