FORMULATION AND EVALUATION OF ATORVASTATIN CALCIUM NANOCRYSTALS CONTAINING P-GLYCOPROTEIN INHIBITORS FOR ENHANCING ORAL DELIVERY

Objective: The main objective of this study was to develop atorvastatin calcium (ATR) as an oral drug delivery system for a P-glycoprotein (P-gp) substrate drug using different pharmaceutical excipients that inhibit P-glycoprotein and evaluate the influence of nanocrystals on the dissolution characteristics and bioavailability compared to the plain drug. Methods: A nanosuspension was prepared by Solvent-antisolvent precipitation method using a solvent containing stabilizer that act as a p-gp inhibitor dissolved in distilled water as polyethylene glycol 300, polyethylene glycol 400 (PEG 300, PEG 400), tween 20 and tween 80 while the solvent selected for atorvastatin calcium was methanol. The concentrations were as follows: PEG 300 and 400 = 0.25% w/v, tween 20 and 80 = 0.75% v/v. Nanocrystals were extracted from the suspension and characterized. Results: Particle size of the drug was 1307±127.79 nm while the formulas prepared ranged from 223±17.67 to 887±58.12 nm. Pure ATR had a saturated solubility of 0.059±0.005 mg/ml and the prepared nanocrystals ranged from 0.32±0.021 to 0.88±0.019 mg/ml. The Percentage of drug released of plain atorvastatin calcium reached 41.49% while the formula ranged from 44.32 to 61.5%. Both XRD and SEM discussed the degree of crystallinity as follows: F1<F2<F4<F3<ATR. Conclusion: 0.3% of PEG 300 and PEG 400 were not enough to formulate proper nanocrystals while 0.75% tween 20 and tween 80 achieved acceptable formulas. F4 which is prepared with tween 80 exhibited the highest enhancement in saturated solubility, dissolution rate and subsequently expected to have improved oral bioavailability

Transubstantiation of reality in El Jarama of Rafael Sánchez Ferlosio and Adrift on the Nile of Naŷīb Maḥfūẓ

Comparative literature follows the most effective bridge of approximation of cultures, an axis of interculturality and a revealing source of the relationships between the different areas of human expression. Counting on this method highlights the confluence between two realistic works, which reveal both the Spanish and Egyptian reality of the mid-twentieth century and, precisely, the fifties in Spain and the sixties in Egypt: The Jarama of Sánchez Ferlosio and Adrift on the Nile of Naŷīb Maḥfūẓ. These works reflect the sufferings and opinions of the poor classes of their respective countries. In the same way, the authors criticized through these novels the passivities of their respective communities. Thus, embody, in this sense, two living examples of the transubstantiation of reality, which converge in many aspects and even in the titles, which are the names of two riversSigue la literatura comparada el puente más eficaz de aproximación de culturas, eje de interculturalidad y fuente reveladora de las relaciones entre las diferentes áreas de la expresión humana. Contándonos con este método se nos destaca la confluencia entre dos obras realistas, que ponen al descubierto la realidad tanto española como egipcia de mitad del siglo XX y, precisamente de los años cincuenta en España y los años sesenta en Egipto: El Jarama de Sánchez Ferlosio y Veladas del Nilo de Naŷīb Maḥfūẓ. Estas obras reflejan los sufrimientos y las opiniones de las clases pobres de sus respectivos países. Del mismo modo, los autores critican a través de estas novelas las pasividades de sus respectivas comunidades. Por ende, encarnan, en este sentido, dos ejemplos vivos de la transubstanciación de la realidad, los cuales se convergen en muchos aspectos e, incluso, en los títulos, que son nombres de dos río

Response of Growth, Flowering and Fruiting of Florida Prince Peach Trees to Spraying with Nanochitosan and Nanosilicon

This study was carried out in the two seasons of 2017 and 2018 on five-year-old peach Florida prince cv. trees grown in sandy silt soil at 3×5 m apart under drip irrigation system of a private peach orchard located at Sharkia Governorate, Egypt. The trees were sprayed with nano-chitosan at 10, 20, 30 and 40 ppm, nano-silicon at 200, 400 and 600 ppm and potassium silicate at 1000, 2000 and 3000 ppm as well as water (control treatment). The results showed that the highest yield / tree, number of harvested fruits / tree and fruit weight for trees treated with nano-chitosan at 10 and 20 ppm in comparison with those sprayed with water and other treatments. Trees were sprayed by nano-silicon at all rates gained the greatest number of flowers/ branch, flower density and fruit set percentage. The trees sprayed with nanosilicin at 600 ppm recorded longest shoot length, largest shoot diameter and highest leaves number/ shoot, while, least values of them were from unsprayed trees (control). The largest leaf area was recorded for trees were sprayed with nano-silicon at 200 ppm, 400 ppm and 600 ppm without significant differences between them

Comparison of drug release from liquid crystalline monoolein dispersions and solid lipid nanoparticles using a flow cytometric technique

AbstractColloidal lipid particles such as solid lipid nanoparticles and liquid crystalline nanoparticles have great opportunities as drug carriers especially for lipophilic drugs intended for intravenous administration. In order to evaluate drug release from these nanoparticles and determine their behavior after administration, emulsion droplets were used as a lipophilic compartment to which the transfer of a model drug was measured. The detection of the model drug transferred from monoolein cubic particles and trimyristin solid lipid nanoparticles into emulsion droplets was performed using a flow cytometric technique. A higher rate and amount of porphyrin transfer from the solid lipid nanoparticles compared to the monoolein cubic particles was observed. This difference might be attributed to the formation of a highly ordered particle which leads to the expulsion of drug to the surface of the crystalline particle. Furthermore, the sponge-like structure of the monoolein cubic particles decreases the rate and amount of drug transferred. In conclusion, the flow cytometric technique is a suitable technique to study drug transfer from these carriers to large lipophilic acceptors. Monoolein cubic particles with their unique structure can be used successfully as a drug carrier with slow drug release compared with trimyristin nanoparticles

Design of Tunable Beamforming Networks Using Metallic Ridge Gap Waveguide Technology

Wireless communication is a leap of development in the history of humanity. For the past 100 years, a considerable effort has been spent to develop better standards, and technologies for a higher speed wireless communication with high system capacity for different applications. This requires the design of a high-frequency, point-to-multipoint antenna array system to achieve the mentioned goals. In addition, the reconfigurability of this antenna system is essential to change the system characteristics to achieve acceptable performance in different situations. The main goal of this thesis is to design a reconfigurable beamforming network to work on the Ka-band for waveguide applications. Among different beamforming networks in the literature, the Butler matrix is chosen due to its higher efficiency and the smaller number of components required than other beamforming networks. The Butler matrix is designed using a dual-plane topology to avoid using crossovers. Ridge gap waveguide technology is chosen among different transmission lines to implement the Butler matrix for several reasons: It does not need dielectrics to operate, so its power handling capacity is defined by the gap height, and it has no dielectric losses. Its zero-field region represents the operating principle for some tunable devices introduced here and its contactless nature, which eases the assembly of waveguide parts at the millimeter-wave frequencies. The reconfigurability of the Butler matrix is implemented such that beamwidth, maximum gain, and beam direction may be all tuned for optimum system performance. To that end, several components are designed to achieve the required target, and strict requirements are placed on several components to achieve an acceptable cascaded-system performance. These components include a ridge gap waveguide 90o-hybrid working over a more than 30% bandwidth, which can provide several coupling levels ranging from 3 dB to 33 dB and a return loss and isolation better than 30 dB. Another component is a wideband reconfigurable power splitter that has a 40% bandwidth, a return loss better than 20 dB in the worst case and the ability to achieve all power splitting ratios including switching between the two guides. In addition, a wideband reconfigurable phase shifter is designed to have 33% bandwidth and phase shift tuning range from 0o to 200o. Two coaxial-to-ridge gap waveguide transitions are designed to work over a more than 100% bandwidth to facilitate testing different ridge gap waveguide components. Analysis of the asymmetric double ridge waveguide is introduced where its impedance is deduced and may be used to design a single to double ridge waveguide transition useful for the dual-plane Butler matrix introduced here. In addition, this concept is used to develop a wideband unequal power divider in the single ridge waveguide technology. At the end, the whole system is assembled to show its performance in different tuning states. The ability of the system to produce radiation patterns of different characteristics is demonstrated. The presented Butler matrix design is a promising beamforming network for several applications like radar, base stations for mobile communications, and satellite applications

Ultra-wide band energy harvesting for ultra-low power electronics applications

In this work, the feasibility of energy harvesting in the useful UWB band (i.e., 3.1-10.6 GHz) is analytically investigated. A typical UWB communications/EH chain in this band is modeled and analyzed, considering the spectral constraints imposed by the federal communications commission (FCC) to UWB signaling. Based on the developed model, accurate analytical expressions are derived for the average received powers of two common types of impulse radio UWB (IR-UWB) signaling waveforms. Numerical simulations on the system-level show excellent agreement with the obtained analytical expressions. Moreover, the DC power levels expected from spectrally constrained IR-UWB waveforms are extremely low (less than 0.3 microwatt) and, accordingly, provide useful guidelines for the design and development of ULP electronics applications in the sub-microwatt range

Magnetic domain microstructure analysis of sintered rare earth magnet materials with high coercivity

Phd ThesisRare earth magnet materials are commonly used in many applications, such as the motors in hybrid and electric vehicles. To improve the magnetic performance of these materials at high temperatures, certain heavy rare earth elements are added to the structure. The high demand and scarcity of heavy rare earth elements have led to a considerable increase in rare earth prices. In this context, more research is being conducted to develop of free rare earth magnets that combine high coercivity and high thermal resistance. The coercivity of sintered permanent magnet materials is controlled by the microstructural parameters of magnet such as grain shape, grain size, grain boundary, and phase morphology. As part of this research effort, a great understanding of the microstructural analysis of materials is vital. In this thesis, different areas have been identified in which improvements can be made in understanding the magnetic domain microstructure of sintered Nd-Fe-B and SmCo magnets with high coercivity. Firstly, this thesis describes the use of magnetic force microscopy (MFM) to investigate the domain structure of sintered rare earth magnet materials in a thermally demagnetised state. Observations are made at both perpendicular and parallel surfaces to the alignment axis. Maze-like magnetic domains and stripe magnetic domains are observed in the perpendicular and parallel surfaces respectively. Branched-like domain patterns are imaged for sintered Nd-Fe-B and Sm2Co17 magnets in the parallel alignment axis. Clear magnetic contrast images in 3D view with defined domain structures are presented. An important microstructural domain patterns are shown in the 3D MFM images such as spike domains and reverse spikes. Samples with wider magnetic domains have spike domain regions, whereas samples with narrower domains exhibit reverse spikes. Secondly, a model is developed that determines the microstructural parameters, such as domain width and domain wall energy, for sintered Nd-Fe-B and SmCo magnets, from the observed MFM images. The domain width and domain wall energy have been determined in the parallel and perpendicular alignment directions. A surface parallel to the alignment axis exhibits a higher domain width and energy compared to that in the perpendicular direction. It is shown that just changing the annealing temperature can have a major effect on the domain width and domain wall energy that leads to change the magnetic properties. In addition the ratio of root-mean-square values for MFM phase images is found to be a good indicator for the variation of magnetic properties. Finally some distorted regions on the topographic image are observed which have a clear effect on MFM image. The effect of the distorted regions on the domain walls is studied using MFM. These regions have been identified using Raman spectroscopy. In addition, the impact of increasing temperature on the distorted regions and their corresponding domain walls is studied using MFM and Raman spectroscopy. The observation are made in-situ and at different locations of sample surface. The distorted regions are increased as the temperature raise. New methods are presented to compute the size of distorted domain walls. The techniques are 2D line profile method and watershed method. The samples studied include both sintered Nd-Fe-B and SmCo materials aimed at understanding the microstructure of sintered Nd-Fe-B and SmCo magnets with a high coercivity.Libyan Ministry of Higher Education and Scientific Research, and Benghazi University

A Study of the Affective Domain in School Science

It has been found that the present science syllabuses to 'O' grade contain material which is of high social relevance. However, normal classroom teaching can take place quite satisfactorily from a certificate point of view but neglect the conscious teaching of these socially important topics. It seems that schools are successful with the cognitive domain but tend to be less successful in helping to develop desirable social attitudes and the willingness to communicate. The purpose of this study is to enable the 'O' grade pupils to develop desirable social attitudes and awareness, change existing attitudes, and as a bonus, to encourage the development of group skills such as communication, co-operation and discussion. Pour topics were chosen for the purpose of the study - "Food and Man" in the third year biology syllabus; "Water Pollution, "Air Pollution" and "Bronchitis and Cancer of the lung", all these three are in the fourth year biology syllabus. Two different kinds of material were prepared, one for the Experimental Group, and the other for the Control Group. For the Experimental Group it included (a) media : games, simulation games, a multimedia package and audio-visual programme; (b) pupil tests; (c) / (c) teacher questionnaire; (d) articles . For the Control Group it included -(a) factual articles; (b) pupil tests; (c) teacher questionnaire. Six schools were chosen for the purpose of the study, and the pupils who used the material were in third and fourth year leading to 'O' grade. The general method of application was that the Experimental Group was provided with the simulation and other new materials, whereas the Control Group was provided with an article containing the same facts as appeared in the simulation, etc. Then both were given the same cognitive and affective tests. Findings showed that the study for the Experimental Group has - (a) provided a useful addition to the work normally carried out in the classrom; (b) contributed to the knowledge reinforcement and recall; (c) helped the pupils to be willing to communicate their understanding to others (through discussion, argument, presentation and reporting); (d) provided the motivation advantage by helping the pupils to develop a high level of interest, enthusiasm and excitement; (e) / (e) helped the pupils to become capable of making their own decisions; (f) encouraged the pupils to be able to work co-operatively with others; (g) provided interaction and peer learning