The Crosstalk of Adipose-Derived Stem Cells (ADSC), Oxidative Stress,and Inflammation in Protective and Adaptive Responses

The potential use of stem cell-based therapies for the repair and regeneration of various tissues and organs is a major goal in repair medicine. Stem cells are classified by their potential to differentiate into functional cells. Compared with other sources, adipose-derived stem cells (ADSCs) have the advantage of being abundant and easy to obtain. ADSCs are considered to be tools for replacing, repairing, and regenerating dead or damaged cells. The capacity of ADSCs to maintain their properties depends on the balance of complex signals in their microenvironment. Their properties and the associated outcomes are in part regulated by reactive oxygen species, which mediate the oxidation-reduction state of cells as a secondary messenger. ADSC therapy has demonstrated beneficial effects, suggesting that secreted factors may provide protection. There is evidence that ADSCs secrete a number of cytokines, growth factors, and antioxidant factors into their microenvironment, thus regulating intracellular signaling pathways in neighboring cells. In this review, we introduce the roles of ADSCs in the protection of cells by modulating inflammation and immunity, and we develop their potential therapeutic properties.     

Pneumocandin Biosynthesis: Involvement of a trans‐Selective Proline Hydroxylase

Echinocandins are cyclic nonribosomal hexapeptides based mostly on nonproteinogenic amino acids and displaying strong antifungal activity. Despite previous studies on their biosynthesis by fungi, the origin of three amino acids, trans‐4‐ and trans‐3‐hydroxyproline, as well as trans‐3‐hydroxy‐4‐methylproline, is still unknown. Here we describe the identification, overexpression, and characterization of GloF, the first eukaryotic α‐ketoglutarate/Fe^II‐dependent proline hydroxylase from the pneumocandin biosynthesis cluster of the fungus Glarea lozoyensis ATCC 74030. In in vitro transformations with L ‐proline, GloF generates trans‐4‐ and trans‐3‐hydroxyproline simultaneously in a ratio of 8:1; the latter reaction was previously unknown for proline hydroxylase catalysis. trans‐4‐Methyl‐L ‐proline is converted into the corresponding trans‐3‐hydroxyproline. All three hydroxyprolines required for the biosynthesis of the echinocandins pneumocandins A₀ and B₀ in G. lozoyensis are thus provided by GloF. Sequence analyses revealed that GloF is not related to bacterial proline hydroxylases, and none of the putative proteins with high sequence similarity in the databases has been characterized so far.     

Solvent Influence on the Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H‐MFI 90 Catalysts

Second generation biofuels are produced in the bioliq® process at the Karlsruhe Institute of Technology via gasification of pyrolysis oil and synthesis of gasoline from the emerging synthesis gas. An alternative strategy is the direct upgrading of the pyrolysis oil by hydrodeoxygenation (HDO). The present study reports on the HDO of guaiacol as one of the phenolic compounds strongly abundant in such mixtures. Special focus was laid on the solvent influence using Pt‐based catalysts. Higher HDO ability was seen using nonpolar solvents and acidic supports. Characterization of the catalysts before and after the test showed that the solvent did not only influence the reactivity, but also the catalyst stability.     

Growth and characterization of hydroxyapatite nanorice on TiO2 nanofibers

Hydroxyapatite (HA) coating with nanoparticles like nanorice is fabricated on chemically pretreated titanium (Ti) surface, through an electrochemical deposition approach, for biomaterial applications. The Ti surface was chemically patterned with anatase TiO₂ nanofibers. These nanofibers were prepared by in situ oxidation of Ti foils in a concentrated solution of H₂O₂ and NaOH, followed by proton exchange and calcinations. Afterward, TiO₂ nanofibers on Ti substrate were coated with HA nanoparticles like nanorice. The obtained samples were annealed at high temperature to produce inter diffusion between TiO₂ and HA layers. The resultant layers were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR), corrosion tests in SBF solution, and Electron Probe Micro Analysis (EPMA). It was found that only Ti from the titanium substrate diffuses into the HA coating and a good corrosion resistance in simulated body fluid was obtained.     

Kinetic and equilibrium study for the sorption of cadmium(II) ions from aqueous phase by eucalyptus bark

The efficiency of eucalyptus bark as a low cost sorbent for removing cadmium ions from aqueous solution has been investigated in batch mode. The equilibrium data could be well described by the Langmuir isotherm but a worse fit was obtained by the Freundlich model. The five linearized forms of the Langmuir equation as well as the non-linear curve fitting analysis method were discussed. Results show that the non-linear method may be a better way to obtain the Langmuir parameters. Maximum cadmium uptake obtained at a temperature of 20 degrees C was 14.53mgg(-1). The influence of temperature on the sorption isotherms of cadmium has been also studied. The monolayer sorption capacity increased from 14.53 to 16.47 when the temperature was raised from 20 to 50 degrees C. The DeltaG degrees values were negative, which indicates that the sorption was spontaneous in nature. The effect of experimental parameters such as contact time, cadmium initial concentration, sorbent dose, temperature, solution initial pH, agitation speed, and ionic strength on the sorption kinetics of cadmium was investigated. Pseudo-second-order model was evaluated using the six linear forms as well as the non-linear curve fitting analysis method. Modeling of kinetic results shows that sorption process is best described by the pseudo-second-order model using the non-linear method. The pseudo-second-order model parameters were function of the initial concentration, the sorbent dose, the solution pH, the agitation speed, the temperature, and the ionic strength.     

Surface and Self-Aggregation Properties of Bis-Benzimidazolones Derivatives of <Emphasis Type="SmallCaps">d</Emphasis>-Glucose

The surface and self-aggregation properties in water of a new series of amphiphilic homologues, bis-benzimidazolone derivatives of d-glucose, were investigated. Parameters such as the maximal surface excess concentration, minimal area per molecule at the interface, and critical micelle concentration (CMC) were found to be significantly dependent on the hydrophobic alkyl chain length. The synthesized compounds form micelles at remarkably low concentrations, and CMCs derived from surface tension measurements show a minimum as a function of the alkyl chain length; this unusual trend can be attributed to the formation of submicellar aggregates in compounds with long alkyl chains, as evidenced from fluorescence probe spectroscopy data. At high surfactant concentrations, lyotropic liquid crystalline phases with hexagonal structure are formed. Small angle X-ray scattering measurements indicate that the characteristic nanoscopic lengths increase with water swelling and alkyl chain length.     

Pilot-Scale Evaluation of H2O2 Injection to Control NOx Emissions

Nitric oxide (NO) in combustion flue gasses can be converted to higher oxidation states by the injection of aqueous solutions of hydrogen peroxide (H2O2) into the hot flue gases. The NO is oxidized to NO2, HNO2, and HNO3, which can then be removed in a wet scrubber. A pilot plant system that was designed, constructed, and operated at Kennedy Space Center confirmed previous results that H2O2 is very effective at oxidizing NO; conversions of NO above 90% were obtained at temperatures of about 500°C (930°F) using mole ratios of H2O2:NOx slightly above 1.0. The mole ratios of H2O2∕NOx needed to obtain high conversions of NO were significantly lower in the pilot plant that they had been in previous laboratory studies, demonstrating that this process can be an economically feasible method for NOx control. The position of the injector and the type of atomization were very important to the efficient utilization of peroxide. When SO2 was present in the flue gas, both NO and SO2 were oxidized without increasing the demand for peroxide.     

Sliding mode approach applied to sensorless direct torque control of cage asynchronous motor via multi-level inverter

To improve the robustness and performance of the dynamic response of a cage asynchronous motor, a direct torque control (DTC) based on sliding mode control (SMC) is adopted to replace traditional proportional-integral (PI) and hysteresis comparators. The combination of the proposed strategy with sinusoidal pulse width modulation (SPWM) applied to a three-level neutral point clamped (NPC) inverter brings many advantages such as a reduction in harmonics, and precise and rapid tracking of the references. Simulations are performed for a three-level inverter with SM-DTC, a two-level inverter with SM-DTC and the three-level inverter with PI-DTC-SPWM. The results show that the SM-DTC method achieves better performance in terms of reference tracking, while adoption of the threelevel inverter topology can effectively reduce the ripples. Applying the SM-DTC to the three-level inverter presents the best solution for achieving efficient and robust control. In addition, the use of a sliding mode speed estimator eliminates the mechanical sensor and this increases the reliability of the system.     

Modified Wilson's Model for Correlating Solubilities in Supercritical Fluids of Some Polycyclic Aromatic Solutes

Since developing mathematical models is extremely useful to determine solubilities of various solutes in supercritical fluids (SCFs); in this work, the “expanded liquid” approach is adopted to predict the solubility of some polycyclic aromatic solutes (with different size, functionality, and polarity) in diverse SCFs. A modified form of the Wilson's model is proposed for predicting the solubilities of the considered binary systems by computation of the activity coefficient based on the local composition concept. Effect of high operating conditions is considered via the variation of the molar volume of the solute. The proposed correlation achieves an overall and average AARD of 9.2% and 7.8%, respectively, on a range of 1.14% to 19.9%, these results show that the predicted solubility data are in good agreement with the experimental ones. Moreover, dependence of binary parameters on density and some solute's characteristics is discussed on the base of their course versus solvent reduced density.     

Hydroxyapatite growth on multiwall carbon nanotubes grown on titanium fibers from a titanium sheet

Nano-hydroxyapatite (HA) was grown on functionalized multiwalled carbon nanotubes (MWCNTs) deposited on TiO₂ nanofibers (NFs) that were hydrothermally grown on Ti metal sheets. The HA was electrochemically grown on the MWCNTs/TiO₂ porous layer. It was found that the HA grows on the MWCNTs/TiO₂ NFs in the form of dense coating with nanorice grain-shaped. The incorporation of MWCNTs between HA and TiO₂ NFs has led to higher adhesion strength as measured by micro-scratching test indicating the benefit of MWCNTs on the improving the bonding strength of HA layer. The obtained coatings exhibit excellent corrosion resistance in simulated body fluid. It is expected that this simple route for preparing the new HA/MWCNTs/TiO₂/Ti-layered structure might be used not only in the biomedical field, but also in catalysis and biological sensing among others.