Synthesis,characterization, and cell viability of bifunctional medical-grade polyurethane nanofiber: Functionalization by bone inducing and bacteria ablating materials

There is an extensive possibility of improving characteristics of fibers used in hard tissue engineering, being hydrophobic and less osteoconductive, resulting in the dynamic growth of new tissues. The current work focuses on the fabrication of nanofibers incorporated with titanium dioxide (TiO₂) ''as osteoconductive'' and silver (Ag) ''as self-healing'' nanoparticles (NPs). The incorporation of AgNO₃ by in situ method not only helped to impart the antibacterial activity but also changed the contact angle from 81 ± 03° in the case of pristine nanofibers to 74 ± 03°, 61 ± 03°, 50 ± 08°, and 39 ± 1.1°, in the composite scaffolds containing 0.01, 0.03, 0.05, and 0.07 M of Ag salts. The incubation in simulated body fluid at 37°C to induce mineralization on nanofiber scaffolds indicated Ca and P crystals' formation. The antibacterial activity showed significantly more toxicity toward E. coli (8.3 ± 0.9 mm) than S. aureus (1.2 ± 0.1 mm). Biocompatibility studies using MTT assay on the pre-osteoblasts showed that both TiO₂ and Ag NPs present in the nanofibers are non-toxic to the bone-like cells. However, results show that a higher concentration of Ag NPs (i.e., 0.07 M) is toxic to cells growing. Finally, all the results suggest that the nanofiber scaffolds have considerable scope for future bone tissue engineering materials.     

A comparison between high-pass and low-pass \Updelta\Upsigma modulators

In this paper, high-pass (HP) $\Updelta\Upsigma$ modulators are compared against the traditional low-pass (LP) $\Updelta\Upsigma$ modulators. The objective of this comparison is to point out the advantages and drawbacks of the two modulators thereby allowing choosing the most suited for a given application. The metrics of comparison are the noise floor, power consumption, area and the effect of the non-idealities of all the basic blocks (i.e., operational transconductance amplifier, quantizer, switches and clocks). The comparative analysis shows that HP modulators are more suited for narrow band applications because of their immunity against DC-offset and flicker noise. For medium and wide band applications, LP modulators are preferred because of their higher robustness against switch imperfections and clock jitter.     

Empty nano and micro‐structured lipid carriers of virgin coconut oil for skin moisturisation

Virgin coconut oil (VCO) is the finest grade of coconut oil, rich in phenolic content, antioxidant activity and contains medium chain triglycerides (MCTs). In this work formulation, characterisation and penetration of VCO‐solid lipid particles (VCO‐SLP) have been studied. VCO‐SLP were prepared using ultrasonication of molten stearic acid and VCO in an aqueous solution. The electron microscopy imaging revealed that VCO‐SLP were solid and spherical in shape. Ultrasonication was performed at several power intensities which resulted in particle sizes of VCO‐SLP ranged from 0.608 ± 0.002 µm to 44.265 ± 1.870 µm. The particle size was directly proportional to the applied power intensity of ultrasonication. The zeta potential values of the particles were from −43.2 ± 0.28 mV to −47.5 ± 0.42 mV showing good stability. The cumulative permeation for the smallest sized VCO‐SLP (0.608 µm) was 3.83 ± 0.01 µg/cm² whereas for larger carriers it was reduced (3.59 ± 0.02 µg/cm²). It is concluded that SLP have the potential to be exploited as a micro/nano scale cosmeceutical carrying vehicle for improved dermal delivery of VCO.Inspec keywords: skin, cosmetics, vegetable oils, ultrasonic applications, electron microscopy, particle sizeOther keywords: empty nanostructured lipid carrier, empty microstructured lipid carrier, virgin coconut oil, skin moisturisation, phenolic content, antioxidant activity, medium chain triglyceride, MCT, VCO‐solid lipid particle, VCO‐SLP, molten stearic acid ultrasonication, electron microscopy imaging, power intensity, particle size, dermal delivery     

Review of microalgae growth in palm oil mill effluent for lipid production

Wastewater treatment using microalgae is an eco-friendly process without secondary pollution. During the process, the wastewater produced is reused, which allows efficient nutrient recycling. This review provides constructive information to enable progress of competent technology for microalgae based productions in palm oil mill effluent (POME). The characteristics of POME that will be described in this paper would be a source of pollution in water if discharged directly. Since microalgae have great potential to be isolated and cultivated in POME, previous studies to improve POME based culture media are still limited. Microalgae are highly competent in diminishing CO₂ emissions and reducing the organic components in POME. In conclusion, biological treatments by using microalgae discussed in this paper and the lipid production from microalgae biomass can be used as an alternative for energy production. The POME treatment with microalgae may meet the standards or limits before being discharged into the water body.     

Flexural and flexural-torsional bifurcation of locally buckled beam-columns

The paper describes the overall bifurcation behaviour of locally buckled I-sections in combined compression and major axis bending. The overall bifurcation loads are calculated using the tangent rigidities of the locally buckled cross-section for minor axis flexure and warping torsion. The expression for the overall bifurcation load is analytic while the tangent rigidities are calculated numerically using an elastic nonlinear finite strip local buckling analysis. It is shown that while the interaction curves for local buckling and overall flexural- torsional buckling of the undistorted cross-section are convex, the interaction curves for the flexural torsional bifurcation of locally buckled beam-columns may be convex, linear or concave depending on the cross-section geometry and the extent of local buckling. It is demonstrated that the overall bifurcation load depends primarily on the local buckling of the flanges. The overall bifurcation load of sections that are locally buckled in the web only is virtually unaffected by local buckling for any combination of bending and compression.     

Buckling Load Prediction in Ortho-Grid Plates for Aerospace Structures

Journal of Failure Analysis and Prevention - Iso-grid structures provide high strength with reduced weights, which is an essential requirement for aerospace applications. Buckling of Ortho-grid...     

Power loss reduction in radial distribution system with multiple distributed energy resources through efficient islanding detection

To provide electric utility service of desired quality at the lowest possible cost, voltage drop and power loss reduction is crucial for distribution network. Distribution systems with Distributed Energy Resources (DER) have shown an enormous potential for power loss and voltage drop reduction. This paper investigates existing islanding detection techniques for feeder performance and proposes a new islanding detection algorithm (NIDA) for node voltage profile improvement and power loss reduction in the distribution network.     

Activation of protein kinase C by intracellular free calcium in the motoneuron cell line NSC-19

Clotrimazole (CLT), a member of the antifungal imidazole family of compounds, has been found to inhibit both calcium (Ca2+)-activated 86Rb and potassium (K) fluxes of human red cells and to inhibit red cell binding of 125I-charybdotoxin (ChTX) [11]. We have now used patch-clamp techniques to demonstrate reversible inhibition of whole cell KCa2+ currents in murine erythroleukemia (MEL) cells by submicromolar concentrations of CLT. Inhibition was equivalent whether currents were elicited by bath application of the Ca2+ ionophore A23187 or by dialyzing cells with a pipette solution containing micromolar concentrations of free Ca2+. The extent of inhibition of whole cell MEL KCa2+ currents was voltage-dependent, decreasing with increasing test potential. We also determined the single channel basis of the CLT inhibition in MEL cells by demonstrating the inhibition of a calcium-activated, ChTX-sensitive K channel by CLT in outside-out patches. The channel was also blocked by the des-imidazolyl metabolite of CLT, 2-chlorophenyl-bisphenyl-methanol (MET II) [15], thus demonstrating that the imidazole ring is not required for the inhibitory action of CLT. Single KCa2+ channels were also evident in inside-out patches of MEL cells. Block of K current by CLT was not unique to MEL cells. CLT also inhibited a component of the whole cell K current in PC12 cells. Channel specificity of block by CLT was determined by examining its effects on other types of voltage-sensitive currents. CLT block showed the following rank order of potency: K currents in PC12 cells > Ca2+ currents in PC12 cells > Na currents in sympathetic neurons. These results demonstrate that direct inhibition of single KCa2+ by CLT can be dissociated from inhibition of cytochrome P-450 in MEL cells.