Solving an inverse problem for a generalized time-delayed Burgers-Fisher equation by Haar wavelet method

In this paper, a numerical method consists of combining Haar wavelet method and Tikhonov regularization method to determine unknown boundary condition and unknown nonlinear source term for the generalized time-delayed Burgers-Fisher equation using noisy data is presented. A stable numerical solution is determined for the problem. We also show that the rate of convergence of the method is as exponential $\Bigl(O\left(\frac{1}{2^{J+1}}\right)\Bigr)$, where $J$ is maximal level of resolution of wavelet. Some numerical results are reported to show the efficiency and robustness of the proposed approach for solving the inverse problems.     

The Growth of Ce,Nd:YAG Single Crystal Under New Atmosphere Condition

Crystallography Reports - Ce3+,Nd3+:YAG single crystal was grown by Czochralski method without using any reduction gas. The growth was done in the atmosphere of pure nitrogen. The limited-flow of...     

Incorporation of two‐dimensional nanomaterials into silk fibroin nanofibers for cardiac tissue engineering

Mimicking the extracellular matrix to have a similar nanofibrous structure regarding electrical conductivity and mechanical properties would be highly beneficial for cardiac tissue engineering. The molybdenum disulfide, MoS₂, and reduced graphene oxide, rGO, nanosheets are two‐dimensional nanomaterials which can be considered as great candidates for enhancing the electrical and mechanical properties of biological scaffolds for cardiac tissue engineering applications. In this study, MoS₂ and rGO nanosheets were synthesized and incorporated into silk fibroin nanofibers, SF, via electrospinning method. Then, the human iPSCs transfected with TBX‐18 gene, TBX18‐hiPSCs, were seeded on these scaffolds for in vitro studies. The MoS₂ and rGO nanosheets were studied by Raman spectroscopy. After incorporation of the nanosheets into SF nanofibers, the associated characterizations were carried out including scanning electron microscopy, transmission electron microscopy, water contact angle, and mechanical test. Furthermore, SF, SF/MoS₂, and SF/rGO scaffolds were used for in vitro studies. Herein, the scaffolds exhibited acceptable biocompatibility and considerable attachment to TBX18‐hiPSCs confirmed by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyl tetrazolium bromide, MTT, assay, and scanning electron microscopy. Also, the real‐time PCR and immunostaining studies confirmed the maturity and upregulation of cardiac functional genes, including GATA‐4, c‐TnT, and α‐MHC in the SF/MoS₂ and SF/rGO scaffolds compared with the bare SF one. Therefore, the reinforcement of these SF‐based scaffolds with MoS₂ and rGO endues them as a suitable candidate for cardiac tissue engineering.     

Syntheses and spectroscopic investigation of some cyclophosphazanes: Analysis of pseudo‐triplet splitting

Some new phosphoramidates, 1–3 , and the corresponding cyclophosphazanes, 4–6 , with formula Cl₂P(p‐NHC₆H₄CH₃) 1 , Cl₂P(O)(p‐NHC₆H₄NO₂) 2 , (CH₃)₂NP(O)Cl(p‐NHC₆H₄CH₃) 3 , [ClP(p‐NC₆H₄CH₃)]₂ 4 , [ClP(O)(p‐NC₆H₄NO₂)]₂ 5 , and [(CH₃)₂NP(O)(p‐NC₆H₄CH₃)]₂ 6 were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR, mass spectroscopy, and elemental analysis. A pseudo‐triplet signal was observed in the ¹H NMR spectrum of molecule 6 for the N(CH₃)₂ protons. The A₆A′ ₆X₂ spin system was suggested for the pseudo‐triplet pattern of ³J_PNCH coupling in this molecule. Ab initio calculations were performed at the HF and B3LYP levels of theory with 6‐311G^** standard basis set on the geometry of compound 6 . Also, the NMR chemical shift calculations were done to compare the computed results with the experimental ones. The calculated results are in good agreement with experimental data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:337–343, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20229     

Separation of <Superscript>133</Superscript>Xe from <Superscript>99</Superscript>Mo, <Superscript>131</Superscript>I and uranium,and removal of impurities using gas chromatography

Summary Separation and purification of ¹³³Xe from acidic solution containing uranium, ⁹⁹Mo and ¹³¹I has been developed. In the first step of this work, uranium pellets were dissolved under pressure (8-15 bar) in 8M nitric acid solution. Then¹³³ Xe and other gases were conducted to activated charcoal cold trap. Final purification of ¹³³Xe from impurities such as NO_x, radioiodine and krypton was performed by passing through a molecular sieve preparative chromatographic column using helium as mobile phase. The final recovery of ¹³³Xe from the separation-purification process was higher than 98%. Adsorption-desorption behavior of radioxenon on the charcoal and molecular sieves have also been studied and discussed.     

Solid state and solution study of some phosphoramidate derivatives containing the P(O)NHC(O) bifunctional group: Crystal structures of CCl2HC(O)NHP(O)(NCH3(CH2C6H5))2, p-ClC6H4C(O)NHP(O)(NCH3(CH2C6H5))2, CCl2HC(O)NHP(O)(N(CH2C6H5)2)2 and p-BrC6H4C(O)NHP(O)(N(CH2C6H5)2)2

Synthetic methods for several novel phosphoramidate compounds containing the P(O)NHC(O) bifunctional group were developed. These compounds with the general formula R₁C(O)NHP(O)(N(R₂)(CH₂C₆H₅))₂, where R₁ = CCl₂H, p-ClC₆H₄, p-BrC₆H₄, o-FC₆H₄ and R₂ = hydrogen, methyl, benzyl, were characterized by several spectroscopic methods and analytical techniques. The effects of phosphorus substituents on the rotation rate around the P–N_amine bond were also investigated. ¹H NMR study of the synthesized compounds demonstrated that the presence of bulky groups attached to the phosphorus center and electron withdrawing groups in the amide moiety lead to large chemical-shift non-equivalence (Δδ_H) of diastereotopic methylene protons. The crystal structures of CCl₂HC(O)NHP(O)(NCH₃(CH₂C₆H₅))₂, p-ClC₆H₄C(O)NHP(O)(NCH₃(CH₂C₆H₅))₂, CCl₂HC(O)NHP(O)(N(CH₂C₆H₅)₂)₂ and p-BrC₆H₄C(O)NHP(O)(N(CH₂C₆H₅)₂)₂ were determined by X-ray crystallography using single crystals. The coordination around the phosphorus center in these compounds is best described as distorted tetrahedral and the P(O) and C(O) groups are anti with respect to each other. In the compound Br-C₆H₄C(O)NHP(O)(N(CH₂C₆H₅)₂)₂ (with two independent molecules in the unit cell), two conformers are connected to each other via two different N–H?O hydrogen bonds forming a non-centrosymmetric dimer. In the crystalline lattice of other compounds, the molecules form centrosymmetric dimers via pairs of same N–H?O hydrogen bonds. The structure of CCl₂HC(O)NHP(O)(N(CH₂C₆H₅)₂)₂ reveals an unusual intramolecular interaction between the oxygen of CO group and amine nitrogen.     

Uptake of curcumin by supported metal oxides (CaO and MgO) mesoporous silica materials

A series of LaMnO₃ perovskites as catalysts for selective reduction of NO by CO were synthesized using microwave and ultrasound assisted sol-gel method. The catalysts were characterized by BET area measurements, Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) techniques. XRD results showed revealed the orthorhobic crystalline structure and with very high purity. SEM analyses proved lower particle size for ultrasound (US) assisted synthesized LaMnO₃. In addition, US assisted synthesized LaMnO₃ presented higher surface area respect to other catalysts, synthesized by the other methods. Results revealed that the ultrasound assisted synthesized catalyst determines the lowest crystallite size, the highest surface area and the highest concentration of O-vacancies and, as a consequence, the highest catalytic activity.

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