Spectrophotometric determination of nicradipine and isradipine in pharmaceutical formulations

A sensitive spectrophotometric method was developed for the determination of some 1,4-dihydropyridine compounds namely, nicardipine and isradipine either in pure form or in pharmaceutical preparations. The method is based on the reduction of nicardipine and isradipine with zinc powder and calcium chloride followed by further reduction with sodium pentacyanoaminoferrate (II) to give violet and red products having the absorbance maximum at 546 and 539 nm with nicardipine and isradipine, respectively. Beer’s law was obeyed over the concentration range 8.0–180 μg/ml with the detection limit of 1.67 μg/ml for nicardipine and 8.0–110 μg/ml with the detection limit of 1.748 μg/ml for isradipine. The analytical parameters and their effects on the reported methods were investigated. The molar absorptivity, quantization limit, standard deviation of intercept (Sa), standard deviation of slope (Sb) and standard deviation of the residuals (Sy/x) were calculated. The composition of the result compounds were found 1:1 for nicardipine and 1:2 for isradipine by Job’s method and the conditional stability constant (Kf) and the free energy changes (ΔG) were calculated for compounds formed. The proposed method was applied successfully for the determination of nicardipine and isradipine in their dosage forms. The results obtained were in good agreement with those obtained using the reference or official methods. A proposal of the reaction pathway was presented

The effect of chitosan nanosilver dressing versus mesenchymal stem cells on wound healing

Background: Wounds constitute a major worldwide public health problem. Infection is the most common complication of wounds. Surgical wound infection is still a major post-operative problem. New modalities for treating wound infections such as nanotechnology and stem cell therapy have been tried. The available studies investigated the effect of either mesenchymal stem cells or Chitosan nanosilver on wound-healing but they didn’t compare their effects. Also, they used biochemical, vascular or immunological studies but not histological ones.Aim: to compare the effect of chitosan nanosilver dressing with the intradermal injection of bone marrow mesenchymal stem cells (BM-MSCs) on wound healing.Methods: 40 adult female albino rats were equally randomized into 4 groups: group I served as control, in group II, surgical wound was induced. In group III chitosan nanosilver dressing was used after wound induction and group IV received intradermal injection of 1x 106mesenchymal stem cells derived from bone marrow after wound induction. All animals were scarified after seven days by decapitation. Prepared sections were subjected to histological (Haematoxylin and Eosin stain, Masson's trichrome stain, periodic acid-Schiff reaction, immunohistochemical stain for proliferating cell nuclear antigen - PCNA and immunoflourescent techniques for labeling mesenchymal stem cells).Results: Wound group showed complete shedding of epidermis, decreased mean optical density of collagen fibers, negative PAS reaction and negative PCNA immunostainning. Chitosan nanosilver dressing group showed significant increase in the mean epidermal thickness, collagen optical density, and the positive PCNA immunoreactivity compared to the mesenchymal stem cells group.Conclusion: Both chitosan nanosilver dressing and mesenchymal stem cells (BM-MSCs) promoted wound healing, but the non-invasive chitosan nanosilver dressing had better and faster wound healing effect.Keywords: Wound healing, Nanosilver, Wound infection, immunofluorescence, mesenchymal stem cell

Comprehensive Study of Various Light Trapping Techniques Used for Sandwiched Thin Film Solar Cell Structures

Thin film solar cells (TFSCs) where first introduced as a low cost alternative to conventional thick ones. TFSCs show low conversion efficiencies due to the used poor quality materials having weak absorption capabilities and to thin absorption layers. In order to increase light absorption within the active layer, specially near its absorption edge, photon management techniques were proposed. These techniques could be implemented on the top of the active layer to enhance the absorption capabilities and/or to act as anti-reflecting coating structures. When used at the back side, their purpose is to prevent the unabsorbed photons from escaping through the back of the cell. In this paper, we coupled the finite difference time-domain (FDTD) algorithm for simulating light interaction within the cell with the commercial simulator Comsol Multiphysics 4.3b for describing carrier transports. In order to model the dispersive and absorption properties of various used materials, their complex refractive indices were estimated using the Lorentzian-Drude (LD) coefficients. We have calculated the absorption profile in the different layers of the cell, the external quantum efficiency and the power conversion efficiency achieved by adding dielectric nanospheres on the top of the active layer. Besides that, the enhancement observed after the addition of dielectric nanospheres at the back side of the active layer was computed. The obtained results are finally compared with the effects of using textured surface and nanowires on the top in plus of cascaded 1D and 2D photonic crystals on the back

Chemical compositions and heavy metal contents of Oreochromis niloticus from the main irrigated canals (rayahs) of Nile Delta

AbstractThe present study aimed to assess the seasonal variations of the proximate chemical composition, physicochemical, microbiological aspects and heavy metal concentrations of Oreochromis niloticus muscles collected from The Nile rayahs from spring 2014 to winter 2015. Rayahs are the main irrigated canals of Nile Delta, Egypt and represent El Tawfiki, El Menoufy, El Behery, and El Nasery rayahs. Results showed a spatial and temporal significant difference (p<0.01) in the proximate composition and Physicochemical aspects of O. niloticus muscles. The moisture, protein, fat, ash, carbohydrates and calorific values varied between (78.55–80.77%), (16.10–17.88%), (1.10–1.95%), (0.55–1.50%), (0.10–0.94%) and (78.37–89.73%), respectively. Heavy metal accumulation in the O. niloticus muscles showed irregular distributions with descending order of: Fe>Zn>Mn>Cu>Pb>Cd. Generally, heavy metals, TVB-N, TMA, TBA and TVC did not exceed the maximum permissible limits in the tissues of O. niloticus. The values of Hazard Index (HI) and Hazard Quotient (HQ) are lower than the acceptable limits, which indicate that the metals in O. niloticus in the Nile rayahs, Egypt, do not pose any particular human health risk concern. Therefore, O. niloticus muscles collected from four rayahs are safe for human consumption and could be used as a source of healthy diet for humans

Refractive index and scattering of porous TiO 2 films

Porous titanium dioxide (TiO2) films are essential components of dye sensitized solar cells (DSSCs) as well as perovskite solar cells (PSCs). Unfortunately, porosity, refractive index, and scattering properties of these films are only roughly known. This induces uncertainties in modelling and understanding of these solar cells. Since the literature provides only descriptions of the optical properties of the porous TiO2 layers with unclear relevance to these solar cells, we investigate porous TiO2 films really used in DSSCs and potentially usable in PSCs. The effective refractive index and the film porosity for different nanostructures that were fabricated from solution-based techniques were determined. The found values are 1.7982 ± 0.005 for the effective refractive index of one kind of TiO2 films and 1.62 ± 0.002 for another one. These values lead to porosities of 53.5% and 65%, respectively. The scattering of the films can be described by a wavelength-independent effective scattering parameter for one film type and by effective scattering particles with a diameter of 46.5 nm for the other film type. The determined porosities are also of relevance for the ionic transport which is functionally crucial in DSSCs and a disturbance in PSCs

A cascaded classification-segmentation reversible system for computer-aided detection and cells counting in microscopic peripheral blood smear basophils and eosinophils images

Computer-aided image analysis has a pivotal role in automated counting and classification of white blood cells (WBCs) in peripheral blood images. Due to their different characteristics, our proposed approach is based on investigating the variations between the basophils and eosinophils in terms of their color histogram, size, and shape before performing the segmentation process. Accordingly, we proposed a cascaded system using a classification-based segmentation process, called classification-segmentation reversible system (CSRS). Prior to applying the CSRS system, a Histogram-based Object to Background Disparity (HOBD) metric was deduced to determine the most appropriate color plane for performing the initial WBC detection (first segmentation). Investigating the local histogram features of both classes resulted in a 92.4% initial classification accuracy using the third-degree polynomial support vector machine (SVM) method. Subsequently, in the proposed CSRS approach, transformation-based segmentation algorithms were developed to fit the specific requirements of each of the two predicted classes. The proposed CSRS system is used, where the images from an initial classification process are fed into a second segmentation process for each class separately. The segmentation results demonstrated a similarity index of 94.9% for basophils, and 94.1% for eosinophils. Moreover, an average counting accuracy of 97.4% for both classes was achieved. In addition, a second classification was carried out after applying the CSRS, achieving a 5.2% increase in accuracy compared to the initial classification process

Prediction of harvestable energy for self-powered wearable healthcare devices: filling a gap

Self-powered or autonomously driven wearable devices are touted to revolutionize the personalized healthcare industry, promising sustainable medical care for a large population of healthcare seekers. Current wearable devices rely on batteries for providing the necessary energy to the various electronic components. However, to ensure continuous and uninterrupted operation, these wearable devices need to scavenge energy from their surroundings. Different energy sources have been used to power wearable devices. These include predictable energy sources such as solar energy and radio frequency, as well as unpredictable energy from the human body. Nevertheless, these energy sources are either intermittent or deliver low power densities. Therefore, being able to predict or forecast the amount of harvestable energy over time enables the wearable to intelligently manage and plan its own energy resources more effectively. Several prediction approaches have been proposed in the context of energy harvesting wireless sensor network (EH-WSN) nodes. In their architectural design, these nodes are very similar to self-powered wearable devices. However, additional factors need to be considered to ensure a deeper market penetration of truly autonomous wearables for healthcare applications, which include low-cost, low-power, small-size, high-performance and lightweight. In this paper, we review the energy prediction approaches that were originally proposed for EH-WSN nodes and critique their application in wearable healthcare devices. Our comparison is based on their prediction accuracy, memory requirement, and execution time. We conclude that statistical techniques are better designed to meet the needs of short-term predictions, while long-term predictions require the hybridization of several linear and non-linear machine learning techniques. In addition to the recommendations, we discuss the challenges and future perspectives of these technique in our review

Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development

The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed by heat treatment. Successfully, quercetin was immobilized on the nanocomposite via physical adsorption to form a quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite. The adhesion of bacteria on the coated-slides was verified after 24 h using confocal laser-scanning microscopy. Results indicated that the quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite had more negativity and higher recovery by glass surfaces than its counterpart. Moreover, coating surfaces with the quercetin-modified nanocomposite lowered both hydrophilicity and surface-attached bacteria compared to surfaces coated with the multi-walled carbon nanotubes/titanium dioxide nanocomposite