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Recent studies suggested that notochordal cells (NCs) and NC-conditioned medium (NCCM) can stimulate cell viability and matrix production of nucleus pulposus cells (NPCs). However, the potential of notochordal cell-rich nucleus pulposus (NRNP) incorporating the native environment of the intervertebral disc (IVD) has not been evaluated. The objective of this study was to develop an optimal NRNP model and test whether it can allow a significant level of NPC activation in vitro. Rabbit NRNP explants were divided into three groups according to different digestion time: digestion NRNP of 8 h, partial digestion NRNP of 2 h, and natural NRNP. Cell viability and NC phenotype were compared between these groups after 14 days of incubation. The products of the selected partial digestion NRNP group were then cocultured with human degenerated NPCs for 14 days. NPC viability, cell proliferation and senescence, the production of glycosaminoglycan (GAG) found in extracellular matrix, and NP matrix production by NPCs were assessed. The results showed that coculturing with partial digestion NRNP significantly improved the cell proliferation, cell senescence, and disc matrix gene expression of NPCs compared with those in the monoculture group. In addition, GAG/DNA ratio in the coculture group increased significantly, while the level of collagen II protein remained unchanged. In this study, we demonstrated that partial digestion NRNP may show a promising potential for NPC regeneration in IVD tissue engineering.

Sulcardine sulfate is a newly developed candidate drug used to control arrhythmias. The aim of this research was to investigate the pharmacokinetics, bioavailability and excretion characteristics of sulcardine in animals. Sprague–Dawley rats were orally and intravenously given sulcardine at 20 and 40 mg/kg. Beagle dogs were also orally and intravenously dosed at 10 mg/kg. Both [3H]-labeled sulcardine and unlabeled sulcardine were given to rats. Feces, urine and bile were collected at 0–72 h for mass balance study. The contents of unlabeled sulcardine and radioactivity in samples were determined by a validated LC–MS/MS method and by liquid scintillation counting, separately. Sulcardine was rapidly eliminated in rats after dosing. The oral bioavailability was 34–35 % in rats, while a higher exposure was observed in dogs (bioavailability = 62.7 %). More than 90 % of dosed sulcardine was recovered, and approximately 20–40 % of the dose excreted into urine as the original form, and the remaining was found in feces and bile, most of which (about 40 %) was transformed into metabolites. No difference was observed between sexes. Metabolism may occur to a large extent after oral administration in rats but to a smaller extent in dogs. Sulcardine was extensively absorbed in both rats and dogs after oral administration. The mass balance data indicated that sulcardine was widely metabolized in rats after oral administration.

Tissue engineering has shown great success in the treatment of intervertebral disk degeneration (IVDD) in the past decade. However, the adverse and harsh microenvironment associated in the intervertebral disks remains a great obstacle for the survival of transplanted cells. Although increasing numbers of new materials have been created or modified to overcome this hurdle, a new effective strategy of biological therapy is still required. In this study, bone morphogenic protein 7 (BMP7)-based functionalized self-assembling peptides were developed by conjugating a bioactive motif from BMP-7 (RKPS) onto the C-terminal of the peptide RADARADARADARADA (RADA16-I) at a ratio of 1:1 to form a new RADARKPS peptide. Human nucleus pulposus-derived stem cells (NPDCs) were cultured in the presence of RADA-RKPS or RADA16-I in an apoptosis-promoting environment that was induced by tumor necrosis factor-alpha, and cells were cultured with RADA16-I in normal medium that served as the control group. After 48 h of apoptosis induction, the viability, proliferation, apoptosis rate, and expression of apoptosis-related genes of NPDCs in the different groups were evaluated, and the differentiation of NPDCs toward nucleus pulposus-like cells was tested. The results showed that the RADA-RKPS peptide could significantly protect the survival and proliferation of NPDCs. In addition, the application of RADA-RKPS decreased the rate of cell apoptosis, as detected by TUNEL-positive staining. Furthermore, our in vitrostudy confirmed the apoptosis-protecting effects of RADA-RKPS peptides, which significantly reduced the BAX/BCL-2 ratio of NPDCs and upregulated the gene expression of collagen II a1, aggrecan, and Sox-9 after 48 h of apoptosis induction. Collectively, these lines of evidence suggest that RADA-RKPS peptides confer a protective effect to NPDCs in an apoptosis environment, suggesting their potential application in the development of new biological treatment strategies for IVDD.

An improved method for the synthesis of α-aminophosphonate based on the Kabachnik-Fields reaction has been developed. The Kabachnik-Fields reactions for the synthesis of the title compounds were investigated in different solvents. The results showed that the solvent-free conditions was optimal for synthesis of this type of compounds.

A series of α-aminophosphonate-functionalized 3-aminopropanols have been efficiently prepared and characterized by 1H, 13C, and 31P NMR and mass spectroscopy. The reaction conditions such as solvent and temperature were thoroughly investigated based on the three-component Kabachnik-Fields reaction. The experimental results revealed that moderate elevation of reaction temperature under solvent-free conditions was optimal for the synthesis of these types of compounds without forming the cyclized byproduct.

A three-component solvent-free method for the synthesis of a series of bis-α-aminophosphonate-modified butanes has been developed. The experimental results showed that the solvent-free reaction conditions without catalyst were optimal for the preparation of this type compounds. The synthesized title compounds were characterized by 1H, 13C, and 31P NMR and mass spectroscopy.

A series of novel 1,6-diaminohexanes functionalized with phosphonates have been synthesized under solvent-free conditions and characterized by NMR and MS. The experimental results indicated that excess aldehyde and phosphite and elevated temperature were required for effective formation of the bis-funcationalized alkyl diamines.

A general and efficient method for the preparation of symmetrical dinucleoside diphosphates with purine bases has been developed. Ap2A and Gp2G were synthesized from the in situ hydrolysis of corresponding nucleoside 5′-phosphoropiperidates with 4,5-dicyanoimidazole as the activator. This method features easily accessible starting materials, simple procedures, and good yield.

Acyclovir β,γ-methylene/dihalomethylenetriphosphates were efficiently synthesized from acyclovir phosphoropiperidate obtained via the redox condensation with 2,2′-dipyridyldisulfide/PPh3 system. Promoted by 4,5-dicyanoimidazole (DCI), the phosphoropiperidate intermediate exhibited high reactivity toward the bisphosphonates.

Between 2009 and 2011, three patients with large-area foot skin retrograde avulsion (more than 1% of the body surface area) underwent venous arterialization. Anastomosis of the artery in the wound surface with the vein in the skin flap and an appropriate number of venous end-to-end anastomoses were performed. The skin flaps survived in all 3 patients. Six months postoperatively, the flap elasticity and appearance were close to that of normal skin, and foot function was better without scar contracture.When venous arterialization is used to treat foot avulsion, the following points should be noted. Surgical indications include no fresh bleeding from the wound edge of the avulsed skin after debridement, more complete avulsed skin, and superficial veins that do not completely separate from the avulsed skin. Venous arterialization is not suitable to avulsion with fresh bleeding, avulsed skin in small fragments, and avulsion with a subcutaneous venous network embolism. During debridement, the subcutaneous venous network should be protected to avoid exposing the vein stems outside the fat layer. If the avulsion is less than 1% of the body surface area, arterial-venous anastomosis can provide adequate blood supply. Venous-venous anastomosis is performed as much as possible to enhance venous return and decrease microcirculatory pressure, which is conducive to the establishment of effective blood circulation.

Stress intensity factors (SIFs) for the cracked circular disks under different distributing surface tractions are evaluated with the scaled boundary finite element method (SBFEM). In the SBFEM, the analytical advantage of the solution in the radial direction allows SIFs to be directly determined from its definition, therefore no special crack-tip treatment is necessary. Furthermore anisotropic material behavior can be treated easily. Different distributions of surface tractions are considered for the center and double-edge-cracked disks. The benchmark examples are modeled and an excellent agreement between the results in the present study and those in published literature is found. It shows that SBFEM is effective and possesses high accuracy. The SIFs of the cracked orthotropic material circular disks subjected to different surface tractions are also evaluated. The technique of substructure is applied to handle the multiple cracks problem.

The theory of Hamiltonian system is introduced for the problems of laminated transversely isotropic magnetoelectroelastic plates. The partial differential equations of the magnetoelectroelastic solids are derived corresponding to the Lagrange density function and Legendre’s transformation. These equations are a set of the first-order Hamiltonian equations and expressed with displacements, electric potential and magnetic potential, as well as their dual variables--lengthways stress, electric displacement and magnetic induction in the symplectic geometry space. To obtain the solutions of the equations, the schemes of separation of variables and expansion of eigenvector of Hamiltonian operator matrix in the polar direction are implemented. The homogenous solutions of the equations consist of zero eigen-solutions and nonzero eigen-solutions. All the eigen-solutions of zero eigenvalue are obtained in the symmetric deformation. These solutions give the classical Saint-Venant’s solutions because the Hamiltonian matrix is symplectic. The method is rational, analytical method and does not require any trial functions.

Hamiltonian dual equation of plane transversely isotropic magnetoelectroelastic solids is derived from variational principle and mixed state Hamiltonian elementary equations are established. Similar to the Hamiltonian formulation in classic dynamics, the z coordinate is treated analogous to the time coordinate. Then the x-direction is discreted with the linear elements to obtain the state-vector governing equations, which are a set of first order differential equations in z and are solved by the analytical approach. Because present approach is analytic in z direction, there is no restriction on the thickness of plate through the use of the present element. Using the propagation matrix method, the approach can be extended to analyze the problems of magnetoelectroelastic laminated plates. Present semi-analytical method of mixed Hamiltonian element has wide application area.

Hamiltonian system used in dynamics is introduced to formulate the three-dimensional problems of the transversely isotropic magnetoelectroelastic solids. The Hamiltonian dual equations in magnetoelectroelastic solids are developed directly from the modified Hellinger-Reissner variational principle derived from generalized Hellinger-Ressner variational principle with two classes of variables. These variables not only include such origin variables as displaces, electric potential and magnetic potential, but also include such their dual variables as lengthways stress, electric displacement and magnetic induction in the symplectic space. Similar to the Hamiltonian formulation in classic dynamics, the z coordinate is treated analogous to the time coordinate so that the method of separation of variables can be used. The governing equations are a set of first order differential equations in z, and the coefficient matrix of the differential equations is Hamiltonian in (x, y).

Heat conduction performance of particle dispersive composites has been numerically investigated by using Finite volume method (FVM) and fractal theory. The effects of the thermal conductivity of particle and polymer matrix, the volume fraction of conductive particle, the dispersion and reunion form of particles on the effective thermal conductivity of composites are analyzed in detail. Results from the research indicate that thermal conductivities of composites will increase nonlinearly along with the increase of filling fraction of particles. Keeping the filling fraction constant, the dispersion and reunion form and direction of particles has significant effect on heat conduction performance of composite. Simple use of high thermal conductivity particles has limited effect on thermal performance of composites. Enhancing the contacts of particle in the direction of heat exchange and forming high heat transfer channels are the main and economical ways to improve heat conduction performance of particulate filled polymer matrix composites.

An improved random walk mode is proposed based on fractal geometry and random walk theory to characterize the features of porous channels quantitatively. Three different types of fractal Sierpinski carpet structures are obtained by iterative method. The effective thermal conductivities and fractal dimensions are calculated by finite volume method and statistical fractal algorithm respectively. The influences of porosity and pore distribution on effective thermal conductivity are investigated. Results indicate that, the effective thermal conductivity may be different for various structures with the same porosity, and the direction of porous channels formed by connected pores is the critical factor. The spectral fractal dimension of porous channels dD in the direction of temperature gradient coincides with the effective thermal conductivity of Sierpinski carpet.

Hamiltonian system used in dynamics is introduced to formulate the transversely isotropic magnetoelectroelastic solids plane problem in rectangular domain and symplectic dual equation is derived corresponding to the generalized variational principle of the magnetoelectroelastic solids. The equation is expressed with displacements, electric potential and magnetic potential, as well as their duality variables--lengthways stress, electric displacement and magnetic induction in the symplectic geometry space. Since the x-coordinate is treated as time variable so that z becomes the independent coordinate in the Hamiltonian matrix operator. The symplectic dual approach enables the separation of variables to work and all the Saint Venant solutions in the symmetric deformation are obtained directly via the zero eigenvalue solutions and all their Jordan normal form of the corresponding Hamiltonian operator matrix and the boundary condition. An example is presented to illustrate the proposed approach.

Abstract: This paper presents a virtual boundary element—integral collocation method (VBEM) for the plane magnetoelectroelastic solids, which is based on the basic idea of the virtual boundary element method for elasticity and the fundamental solutions of the plane magnetoelectroelastic solids. Besides sharing all the advantages of the conventional boundary element method (BEM) over domain discretization methods, it avoids the computation of singular integral on the boundary by introducing the virtual boundary. In the end, several numerical examples are performed to demonstrate the performance of this method, and the results show that they agree well with the exact solutions. The method is one of the efficient numerical methods used to analyze megnatoelectroelastic solids. [Copyright &y& Elsevier]

In this paper, 18 symmetric hydrazo compounds undergo rapid oxidation to corresponding azo compounds using NaNO2/NaHSO4•H2O/SiO2as a novel oxidising agent under mild conditions for the first time.

In this paper 18 aryl substituted semicarbazides undergo rapid oxidation to the corresponding aryl azo compounds using NaNO2-acetic anhydride as a novel oxidizing agent under mild conditions for the first time.

Ten diaryl carbazide are shown to undergo selective and rapid oxidation to the diaryl carbazones using NaNO2/NaHSO4• H2O/SiO2as a novel mild oxidising agent.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.