Preparation and characterization of novel chitosan/nanodiopside/nanohydroxyapatite composite scaffolds for tissue engineering applications

Chitosan/nanodiopside/nanohydroxyapatite (CS/nDP/nHAp) composite scaffolds were prepared from the mixture of chitosan, nDP, and nHAp in different inorganic/organic weight ratios by using the freeze-drying method. The prepared nHAp and composite scaffolds were investigated using BET, TG, FT-IR, SEM, EDS, and XRD techniques. The composite scaffolds had 50–85% porosities with interlinked porous networks. Moreover, investigation of the cell proliferation, adhesion, and viability using MTT test, and mouse preosteoblast cell proved the cytocompatibile nature of the composite scaffolds with improved cell attachment and proliferation. All these results essentially illustrated that this composite could be a potential for bone tissue engineering applications.     

Inhibition of growth of a murine squamous cell carcinoma by a cyclooxygenase inhibitor increases leukotriene B4 production

OBJECTIVE: To determine the role of metabolites of arachidonic acid in the growth of squamous cell carcinomas of the head and neck. DESIGN: Investigation of the effect of a cyclooxygenase inhibitor, piroxicam, on the growth of squamous cell carcinoma in a murine model. INTERVENTION: C3H/HeJ mice bearing squamous cell carcinoma (SCCVII) were treated with piroxicam (0.08 mg/d, orally) for 30 days beginning 1 day before tumor inoculation. MAIN OUTCOME MEASURES: Decrease in tumor volumes and tumor growth rates. RESULTS: Significant inhibition of tumor growth (P = .002) and final tumor weight (P = .0007) was noted in the group receiving piroxicam therapy. Prostaglandin E2 levels in the tumor tissue were unrelated to treatment or tumor size. Increased levels of leukotriene B4 were observed in the piroxicam-treated group (P = .03), and larger tumors were associated with decreased leukotriene B4 levels (P = .0001). CONCLUSIONS: Cyclooxygenase inhibitors may be effective in the treatment of some squamous cell carcinomas. The therapeutic effect of cyclooxygenase inhibitors may result from shunting into the lipoxygenase pathway of arachidonic acid metabolism.     

Experimental study of the effect of fuel types on the performance of spark ignition engine

Different fuels are being used daily in the city of Kirkuk, Iraq for operating vehicles with spark-ignition internal combustion engines. Aiming to address the effects of these fuels on both engines and the environment, this work conducts an experimental study where a single-cylinder, four-stroke small spark ignition engine is employed. Three types of benzene with different octane ratings (low with an additive [85.8%], medium [89.2%], and high [95.6%]) are utilized in the study as they are the most consumed fuel in the area of the study. Moreover, the low-octane fuel will be addressed with a commercial additive. In addition to engine performance, the exhaust gases and sound levels are analyzed as well. Through the outcomes, it is observed that the fuel with higher octane numbers relatively produces better engine performance and pollution. At normal engine speed, the fuel with a medium octane rating, however, has close engine performance results but with worse pollution effects. On the other hand, the engine fails to start with low-octane fuel without the additive. The additive improves the engine performance with the low octane fuel and surprisingly produces fewer pollution gases than the fuel with medium octane number. However, the engine still behaves worse than with the other fuels at normal engine speed.     

Spectral resolution enhancement of plasmonic color mixing sensor with extremely compact footprint and wide range tuning

Microsystem Technologies - The plasmonic structures (PSs) are promising candidate for mixing colors as a color filter detection with the very small size of sensor and high spectral resolution....     

A comparative study of the performance characteristics of double‐effect absorption refrigeration systems

Three classes of double‐effect lithium bromide–water absorption refrigeration systems (series, parallel and reverse parallel) with identical refrigeration capacities are studied and compared thermodynamically. In order to simulate the performances of the systems, a new set of computationally efficient formulations is used for thermodynamic properties of Li‐Br solutions at equilibrium. The simulation results are used to examine the influence of various operating parameters on the first and second law performance characteristics of the systems. In addition, the dependences are investigated of system performance on the effectivenesses of the solution heat exchangers, the pressure drops between the evaporator and the absorber and between the low‐pressure generator and the condenser, and the low‐grade heat externally supplied to the low‐pressure generator. The results reveal the advantages and disadvantages of different configurations of double‐effect lithium bromide–water absorption refrigeration systems, and are expected to be useful in the design and control of such systems. Copyright © 2010 John Wiley & Sons, Ltd.     

Cu and Cu-SWCNT Nanoparticles’ Suspension in Pulsatile Casson Fluid Flow via Darcy–Forchheimer Porous Channel with Compliant Walls: A Prospective Model for Blood Flow in Stenosed Arteries

The use of experimental relations to approximate the efficient thermophysical properties of a nanofluid (NF) with Cu nanoparticles (NPs) and hybrid nanofluid (HNF) with Cu-SWCNT NPs and subsequently model the two-dimensional pulsatile Casson fluid flow under the impact of the magnetic field and thermal radiation is a novelty of the current study. Heat and mass transfer analysis of the pulsatile flow of non-Newtonian Casson HNF via a Darcy–Forchheimer porous channel with compliant walls is presented. Such a problem offers a prospective model to study the blood flow via stenosed arteries. A finite-difference flow solver is used to numerically solve the system obtained using the vorticity stream function formulation on the time-dependent governing equations. The behavior of Cu-based NF and Cu-SWCNT-based HNF on the wall shear stress (WSS), velocity, temperature, and concentration profiles are analyzed graphically. The influence of the Casson parameter, radiation parameter, Hartmann number, Darcy number, Soret number, Reynolds number, Strouhal number, and Peclet number on the flow profiles are analyzed. Furthermore, the influence of the flow parameters on the non-dimensional numbers such as the skin friction coefficient, Nusselt number, and Sherwood number is also discussed. These quantities escalate as the Reynolds number is enhanced and reduce by escalating the porosity parameter. The Peclet number shows a high impact on the microorganism’s density in a blood NF. The HNF has been shown to have superior thermal properties to the traditional one. These results could help in devising hydraulic treatments for blood flow in highly stenosed arteries, biomechanical system design, and industrial plants in which flow pulsation is essential.     

Business model archetypes for data marketplaces in the automotive industry

Policymakers and analysts are heavily promoting data marketplaces to foster data trading between companies. Existing business model literature covers individually owned, multilateral data marketplaces. However, these particular types of data marketplaces hardly reach commercial exploitation. This paper develops business model archetypes for the full array of data marketplace types, ranging from private to independent ownership and from a hierarchical to a market orientation. Through exploratory interviews and case analyses, we create a business model taxonomy. Patterns in our taxonomy reveal four business model archetypes. We find that privately-owned data marketplaces with hierarchical orientation apply the aggregating data marketplace archetype. Consortium-owned data marketplaces apply the archetypes of aggregating data marketplace with additional brokering service and consulting data marketplace. Independently owned data marketplaces with market orientation apply the facilitating data marketplace archetype. Our results provide a basis for configurational theory that explains the performance of data marketplace business models. Our results also provide a basis for specifying boundary conditions for theory on data marketplace business models, as, for instance, the importance of network effects differs strongly between the archetypes.

     

Hardware Architecture for Guessing Random Additive Noise Decoding Markov Order (GRAND-MO)

Journal of Signal Processing Systems - Communication channels with memory are often sensitive to burst noise, which drastically reduces the decoding performance of standard channel code decoders,...