Effects of Wnt-10b on proliferation and differentiation of adult murine skin-derived CD34 and CD49f double-positive cells

Although mouse Wnt-10b has been shown to play various roles in a wide range of biological actions, the effects on epithelial stem/progenitor cells in the skin have not been reported. In the present study, we investigated the effects of Wnt-10b on proliferation and differentiation of murine skin-derived CD34 and CD49f double-positive (CD34⁺CD49f⁺) cells, a supposed fraction as enriched epithelial stem/progenitor cells. The cells were prepared from dorsal skin samples obtained from young adult mice as α6 integrin (CD49f) and CD34 double-positive cells by fluorescent activated cell sorting (FACS), and they were cultured with or without Wnt-10b to investigate its effects on proliferation and differentiation. Involvement of canonical Wnt signaling pathway was confirmed by TOPFLASH assay, and differentiation of the CD34⁺CD49f⁺ cells was assessed by RT-PCR analysis and immunocytochemical examinations. The skin-derived CD34⁺CD49f⁺ cells were immunopositive for Lhx2 and expressed mRNA of classical markers for bulge stem cells, including Lhx2, keratin15, Sox9, S100a6, and NFATc1. Their proliferation was suppressed by Wnt-10b, and the markers for differentiated epithelial cells became to be expressed in the culture with Wnt-10b. These results suggest that Wnt-10b promotes differentiation of epithelial stem/progenitor cells in the skin.     

Inhibition of hydrogen oxidation by HBr and Br2

The high-temperature bromine chemistry was updated and the inhibition mechanisms involving HBr and Br₂ were re-examined. The thermochemistry of the bromine species was obtained using the Active Thermochemical Tables (ATcT) approach, resulting in improved data for, among others, Br, HBr, HOBr and BrO. Ab initio calculations were used to obtain rate coefficients for selected reactions of HBr and HOBr, and the hydrogen/bromine/oxygen reaction mechanism was updated. The resulting model was validated against selected experimental data from the literature and used to analyze the effect of HBr and Br₂ on laminar, premixed hydrogen flames. Our work shows that hydrogen bromide and molecular bromine act differently as inhibitors in flames. For HBr, the reaction HBr + H ? H₂ + Br (R2) is rapidly equilibrated, depleting HBr in favor of atomic Br, which is the major bromine species throughout the reaction zone. The chain-breaking steps are then H + Br + M → HBr + M (R1), Br + HO₂ → HBr + O₂ (R7), and Br + Br + M → Br₂ + M (R8). In Br₂-doped flames, the reaction Br₂ + H ? HBr + Br (R9) is far from equilibration and serves to deplete H in the reaction zone by competing with H + O₂ → O + OH. The inhibition is augmented by recombination of Br (R8). If the inlet Br₂ mole fraction exceeds about 20%, reactions (R8), (R2) are both reversed, now acting to promote chain branching and increase the flame speed. According to the present model, cycles involving HOBr are not important for generation or removal of chain carriers in these flames.     

A wide range kinetic modeling study of pyrolysis and oxidation of methyl butanoate and methyl decanoate – Note II: Lumped kinetic model of decomposition and combustion of methyl esters up to methyl decanoate

The aim of this work is to develop and discuss a lumped kinetic model to simulate the pyrolysis and combustion behavior of methyl decanoate. Validation of the lumped kinetic model of methyl decanoate in a very wide range of conditions, with temperature ranging from 500 to more than 2000 K, pressures up to 16 bar and equivalent ratios from lean to pyrolysis conditions, proved that, despite the drastic simplifications, the model can properly reproduce the experimental measurements in pyrolysis as well as in an oxidation environment, in both the low temperature regime and in flame conditions. This model is an extension of the lumped model of methyl butanoate developed and discussed in the first part of this work [1]. Thus, the lumped kinetic model of methyl butanoate and methyl decanoate is also quite simply applied to simulating the combustion behavior of intermediate methyl esters, by using the lever rule between the two reference components. The overall agreement with experimental measurements is very encouraging and lays the basis for the extension to the lumped kinetic scheme to soy and rapeseed biodiesel fuels.     

Synthetic strategies and structural aspects of metal-mediated multiporphyrin assemblies

Porphyrins play a major role as active chromophores in artificial systems mimicking the natural photoinduced processes. The formation of coordination bonds between peripheral donor sites on the porphyrins and external metal fragments has proven to be an efficient alternative to covalent synthesis for the construction of multiporphyrin assemblies, whose complexity and beauty gradually approach those of the multichromophore systems found in nature. In a modular approach, relatively simple metal-mediated porphyrin adducts, owing to their thermodynamic and kinetic stability, can be exploited as building blocks in the construction of higher order architectures. Thus, multichromophore systems become accessible on demand, with a limited synthetic effort. The collection of solid-state structures reported here demonstrates that the flexibility of the porphyrins and the metal junctions, combined with the conformational freedom of the coordination bonds, may lead to assemblies with hardly predictable architectures. Examples in which X-ray structural determination was essential for establishing the real composition and geometry of the multiporphyrin assemblies are highlighted.     

Optimization of Inhibitors of Mycobacterium tuberculosis Pantothenate Synthetase Based on Group Efficiency Analysis

Ligand efficiency has proven to be a valuable concept for optimization of leads in the early stages of drug design. Taking this one step further, group efficiency (GE) evaluates the binding efficiency of each appendage of a molecule, further fine‐tuning the drug design process. Here, GE analysis is used to systematically improve the potency of inhibitors of Mycobacterium tuberculosis pantothenate synthetase, an important target in tuberculosis therapy. Binding efficiencies were found to be distributed unevenly within a lead molecule derived using a fragment‐based approach. Substitution of the less efficient parts of the molecule allowed systematic development of more potent compounds. This method of dissecting and analyzing different groups within a molecule offers a rational and general way of carrying out lead optimization, with potential broad application within drug discovery.     

Isolation and characterization of murine hepatocytes following collagenase infusion into left ventricle of heart

A method for obtaining mouse hepatocytes by infusing collagenase solution into the left ventricle was established. This technique was shown to be equivalent to the intra-portal infusion method and more practical, especially in postnatal mice with a small body size.     

JPEG2000-coded image error concealment exploiting convex sets projections.

Transmission errors in JPEG2000 can be grouped into three main classes, depending on the affected area: LL, high frequencies at the lower decomposition levels, and high frequencies at the higher decomposition levels. The first type of errors are the most annoying but can be concealed exploiting the signal spatial correlation like in a number of techniques proposed in the past; the second are less annoying but more difficult to address; the latter are often imperceptible. In this paper, we address the problem of concealing the second class or errors when high bit-planes are damaged by proposing a new approach based on the theory of projections onto convex sets. Accordingly, the error effects are masked by iteratively applying two procedures: low-pass (LP) filtering in the spatial domain and restoration of the uncorrupted wavelet coefficients in the transform domain. It has been observed that a uniform LP filtering brought to some undesired side effects that negatively compensated the advantages. This problem has been overcome by applying an adaptive solution, which exploits an edge map to choose the optimal filter mask size. Simulation results demonstrated the efficiency of the proposed approach.